Release v5.3.9

Use MessageSource in HandlerMethod for error reason
Closes gh-27156
2026-06-08 17:33:33 +00:00 · 2021-07-14 06:36:18 +00:00 · 2021-07-13 19:38:58 +01:00 · 2021-07-13 18:29:34 +02:00 · 2021-07-13 16:32:12 +01:00 · 2021-07-13 14:55:25 +02:00
325 changed files with 4438 additions and 2455 deletions
@@ -72,7 +72,7 @@ to start a discussion first or have already created an issue, once a pull reques
 created, we will close the issue as superseded by the pull request, and the discussion
 about the issue will continue under the pull request.

-1. Always check out the `master` branch and submit pull requests against it
+1. Always check out the `main` branch and submit pull requests against it
 (for target version see [settings.gradle](settings.gradle)).
 Backports to prior versions will be considered on a case-by-case basis and reflected as
 the fix version in the issue tracker.
@@ -1,7 +1,7 @@
 plugins {
 	id 'io.spring.dependency-management' version '1.0.9.RELEASE' apply false
 	id 'io.spring.nohttp' version '0.0.5.RELEASE'
-	id 'org.jetbrains.kotlin.jvm' version '1.5.0' apply false
+	id 'org.jetbrains.kotlin.jvm' version '1.5.21' apply false
 	id 'org.jetbrains.dokka' version '0.10.1' apply false
 	id 'org.asciidoctor.jvm.convert' version '3.1.0'
 	id 'org.asciidoctor.jvm.pdf' version '3.1.0'
@@ -10,7 +10,7 @@ plugins {
 	id "com.github.ben-manes.versions" version '0.28.0'
 	id "com.github.johnrengelman.shadow" version "6.1.0" apply false
 	id "me.champeau.jmh" version "0.6.4" apply false
-	id "org.jetbrains.kotlin.plugin.serialization" version "1.5.0" apply false
+	id "org.jetbrains.kotlin.plugin.serialization" version "1.5.21" apply false
 	id "org.unbroken-dome.xjc" version '2.0.0' apply false
 }

@@ -27,16 +27,16 @@ configure(allprojects) { project ->

 	dependencyManagement {
 		imports {
-			mavenBom "com.fasterxml.jackson:jackson-bom:2.12.3"
-			mavenBom "io.netty:netty-bom:4.1.63.Final"
-			mavenBom "io.projectreactor:reactor-bom:2020.0.7"
-			mavenBom "io.r2dbc:r2dbc-bom:Arabba-SR9"
-			mavenBom "io.rsocket:rsocket-bom:1.1.0"
-			mavenBom "org.eclipse.jetty:jetty-bom:9.4.40.v20210413"
-			mavenBom "org.jetbrains.kotlin:kotlin-bom:1.5.0"
-			mavenBom "org.jetbrains.kotlinx:kotlinx-coroutines-bom:1.4.3"
-			mavenBom "org.jetbrains.kotlinx:kotlinx-serialization-bom:1.2.0"
-			mavenBom "org.junit:junit-bom:5.7.1"
+			mavenBom "com.fasterxml.jackson:jackson-bom:2.12.4"
+			mavenBom "io.netty:netty-bom:4.1.65.Final"
+			mavenBom "io.projectreactor:reactor-bom:2020.0.9"
+			mavenBom "io.r2dbc:r2dbc-bom:Arabba-SR10"
+			mavenBom "io.rsocket:rsocket-bom:1.1.1"
+			mavenBom "org.eclipse.jetty:jetty-bom:9.4.43.v20210629"
+			mavenBom "org.jetbrains.kotlin:kotlin-bom:1.5.21"
+			mavenBom "org.jetbrains.kotlinx:kotlinx-coroutines-bom:1.5.1"
+			mavenBom "org.jetbrains.kotlinx:kotlinx-serialization-bom:1.2.1"
+			mavenBom "org.junit:junit-bom:5.7.2"
 		}
 		dependencies {
 			dependencySet(group: 'org.apache.logging.log4j', version: '2.14.1') {
@@ -51,7 +51,7 @@ configure(allprojects) { project ->
 			}
 			dependency "com.google.code.findbugs:jsr305:3.0.2"

-			dependencySet(group: 'org.aspectj', version: '1.9.6') {
+			dependencySet(group: 'org.aspectj', version: '1.9.7') {
 				entry 'aspectjrt'
 				entry 'aspectjtools'
 				entry 'aspectjweaver'
@@ -67,18 +67,18 @@ configure(allprojects) { project ->
 			dependency "io.reactivex:rxjava:1.3.8"
 			dependency "io.reactivex:rxjava-reactive-streams:1.2.1"
 			dependency "io.reactivex.rxjava2:rxjava:2.2.21"
-			dependency "io.reactivex.rxjava3:rxjava:3.0.12"
+			dependency "io.reactivex.rxjava3:rxjava:3.0.13"
 			dependency "io.projectreactor.tools:blockhound:1.0.4.RELEASE"

 			dependency "com.caucho:hessian:4.0.63"
-			dependency "com.fasterxml:aalto-xml:1.2.2"
+			dependency "com.fasterxml:aalto-xml:1.3.0"
 			dependency("com.fasterxml.woodstox:woodstox-core:6.2.6") {
 				exclude group: "stax", name: "stax-api"
 			}
-			dependency "com.google.code.gson:gson:2.8.6"
-			dependency "com.google.protobuf:protobuf-java-util:3.15.8"
+			dependency "com.google.code.gson:gson:2.8.7"
+			dependency "com.google.protobuf:protobuf-java-util:3.17.3"
 			dependency "com.googlecode.protobuf-java-format:protobuf-java-format:1.4"
-			dependency("com.thoughtworks.xstream:xstream:1.4.16") {
+			dependency("com.thoughtworks.xstream:xstream:1.4.17") {
 				exclude group: "xpp3", name: "xpp3_min"
 				exclude group: "xmlpull", name: "xmlpull"
 			}
@@ -91,7 +91,7 @@ configure(allprojects) { project ->
 				entry 'jibx-run'
 			}
 			dependency "org.ogce:xpp3:1.1.6"
-			dependency "org.yaml:snakeyaml:1.28"
+			dependency "org.yaml:snakeyaml:1.29"

 			dependency "com.h2database:h2:1.4.200"
 			dependency "com.github.ben-manes.caffeine:caffeine:2.9.1"
@@ -100,7 +100,7 @@ configure(allprojects) { project ->
 			dependency "commons-io:commons-io:2.5"
 			dependency "io.vavr:vavr:0.10.3"
 			dependency "net.sf.jopt-simple:jopt-simple:5.0.4"
-			dependencySet(group: 'org.apache.activemq', version: '5.16.1') {
+			dependencySet(group: 'org.apache.activemq', version: '5.16.2') {
 				entry 'activemq-broker'
 				entry('activemq-kahadb-store') {
 					exclude group: "org.springframework", name: "spring-context"
@@ -116,29 +116,29 @@ configure(allprojects) { project ->
 			dependency "org.apache.poi:poi-ooxml:4.1.2"
 			dependency "org.apache-extras.beanshell:bsh:2.0b6"
 			dependency "org.freemarker:freemarker:2.3.31"
-			dependency "org.hsqldb:hsqldb:2.5.1"
+			dependency "org.hsqldb:hsqldb:2.5.2"
 			dependency "org.quartz-scheduler:quartz:2.3.2"
 			dependency "org.codehaus.fabric3.api:commonj:1.1.0"
 			dependency "net.sf.ehcache:ehcache:2.10.6"
 			dependency "org.ehcache:jcache:1.0.1"
 			dependency "org.ehcache:ehcache:3.4.0"
-			dependency "org.hibernate:hibernate-core:5.4.31.Final"
+			dependency "org.hibernate:hibernate-core:5.4.32.Final"
 			dependency "org.hibernate:hibernate-validator:6.2.0.Final"
-			dependency "org.webjars:webjars-locator-core:0.46"
+			dependency "org.webjars:webjars-locator-core:0.47"
 			dependency "org.webjars:underscorejs:1.8.3"

-			dependencySet(group: 'org.apache.tomcat', version: '9.0.45') {
+			dependencySet(group: 'org.apache.tomcat', version: '9.0.50') {
 				entry 'tomcat-util'
 				entry('tomcat-websocket') {
 					exclude group: "org.apache.tomcat", name: "tomcat-websocket-api"
 					exclude group: "org.apache.tomcat", name: "tomcat-servlet-api"
 				}
 			}
-			dependencySet(group: 'org.apache.tomcat.embed', version: '9.0.45') {
+			dependencySet(group: 'org.apache.tomcat.embed', version: '9.0.50') {
 				entry 'tomcat-embed-core'
 				entry 'tomcat-embed-websocket'
 			}
-			dependencySet(group: 'io.undertow', version: '2.2.7.Final') {
+			dependencySet(group: 'io.undertow', version: '2.2.8.Final') {
 				entry 'undertow-core'
 				entry('undertow-websockets-jsr') {
 					exclude group: "org.jboss.spec.javax.websocket", name: "jboss-websocket-api_1.1_spec"
@@ -159,11 +159,11 @@ configure(allprojects) { project ->
 			dependency("org.apache.httpcomponents:httpasyncclient:4.1.4") {
 				exclude group: "commons-logging", name: "commons-logging"
 			}
-			dependency 'org.apache.httpcomponents.client5:httpclient5:5.0.3'
-			dependency 'org.apache.httpcomponents.core5:httpcore5-reactive:5.0.3'
-			dependency "org.eclipse.jetty:jetty-reactive-httpclient:1.1.6"
+			dependency 'org.apache.httpcomponents.client5:httpclient5:5.1'
+			dependency 'org.apache.httpcomponents.core5:httpcore5-reactive:5.1.1'
+			dependency "org.eclipse.jetty:jetty-reactive-httpclient:1.1.9"

-			dependency "org.jruby:jruby:9.2.16.0"
+			dependency "org.jruby:jruby:9.2.19.0"
 			dependency "org.python:jython-standalone:2.7.1"
 			dependency "org.mozilla:rhino:1.7.11"

@@ -189,25 +189,25 @@ configure(allprojects) { project ->
 			dependency "org.testng:testng:7.4.0"
 			dependency "org.hamcrest:hamcrest:2.1"
 			dependency "org.awaitility:awaitility:3.1.6"
-			dependency "org.assertj:assertj-core:3.19.0"
+			dependency "org.assertj:assertj-core:3.20.2"
 			dependencySet(group: 'org.xmlunit', version: '2.8.2') {
 				entry 'xmlunit-assertj'
 				entry('xmlunit-matchers') {
 					exclude group: "org.hamcrest", name: "hamcrest-core"
 				}
 			}
-			dependencySet(group: 'org.mockito', version: '3.9.0') {
+			dependencySet(group: 'org.mockito', version: '3.11.0') {
 				entry('mockito-core') {
 					exclude group: "org.hamcrest", name: "hamcrest-core"
 				}
 				entry 'mockito-junit-jupiter'
 			}
-			dependency "io.mockk:mockk:1.10.2"
+			dependency "io.mockk:mockk:1.11.0"

-			dependency("net.sourceforge.htmlunit:htmlunit:2.49.1") {
+			dependency("net.sourceforge.htmlunit:htmlunit:2.51.0") {
 				exclude group: "commons-logging", name: "commons-logging"
 			}
-			dependency("org.seleniumhq.selenium:htmlunit-driver:2.49.1") {
+			dependency("org.seleniumhq.selenium:htmlunit-driver:2.51.0") {
 				exclude group: "commons-logging", name: "commons-logging"
 			}
 			dependency("org.seleniumhq.selenium:selenium-java:3.141.59") {
@@ -236,7 +236,7 @@ configure(allprojects) { project ->
 			dependency "com.ibm.websphere:uow:6.0.2.17"
 			dependency "com.jamonapi:jamon:2.82"
 			dependency "joda-time:joda-time:2.10.10"
-			dependency "org.eclipse.persistence:org.eclipse.persistence.jpa:2.7.8"
+			dependency "org.eclipse.persistence:org.eclipse.persistence.jpa:2.7.9"
 			dependency "org.javamoney:moneta:1.3"

 			dependency "com.sun.activation:javax.activation:1.2.0"
@@ -316,7 +316,7 @@ configure([rootProject] + javaProjects) { project ->
 			kotlinOptions {
 				languageVersion = "1.3"
 				apiVersion = "1.3"
-				freeCompilerArgs = ["-Xjsr305=strict", "-Xsuppress-version-warnings"]
+				freeCompilerArgs = ["-Xjsr305=strict", "-Xsuppress-version-warnings", "-Xopt-in=kotlin.RequiresOptIn"]
 				allWarningsAsErrors = true
 			}
 		}
@@ -336,7 +336,7 @@ configure([rootProject] + javaProjects) { project ->
 	}

 	checkstyle {
-		toolVersion = "8.42"
+		toolVersion = "8.44"
 		configDirectory.set(rootProject.file("src/checkstyle"))
 	}

@@ -375,10 +375,10 @@ configure([rootProject] + javaProjects) { project ->
 			"https://fasterxml.github.io/jackson-core/javadoc/2.10/",
 			"https://fasterxml.github.io/jackson-databind/javadoc/2.10/",
 			"https://fasterxml.github.io/jackson-dataformat-xml/javadoc/2.10/",
-			"https://hc.apache.org/httpcomponents-client-ga/httpclient/apidocs/",
+			"https://hc.apache.org/httpcomponents-client-5.1.x/current/httpclient5/apidocs/",
 			"https://projectreactor.io/docs/test/release/api/",
 			"https://junit.org/junit4/javadoc/4.13.2/",
-			"https://junit.org/junit5/docs/5.7.1/api/"
+			"https://junit.org/junit5/docs/5.7.2/api/"
 	] as String[]
 }

@@ -1,4 +1,4 @@
-version=5.3.7-SNAPSHOT
+version=5.3.9
 org.gradle.jvmargs=-Xmx1536M
 org.gradle.caching=true
 org.gradle.parallel=true
@@ -103,9 +103,12 @@ dokka {
 		externalDocumentationLink {
 			url = new URL("https://www.reactive-streams.org/reactive-streams-1.0.1-javadoc/")
 		}
+/*
+		This link causes errors, removing to fix the build.
 		externalDocumentationLink {
 			url = new URL("https://kotlin.github.io/kotlinx.coroutines/kotlinx-coroutines-core/")
 		}
+*/
 		externalDocumentationLink {
 			url = new URL("https://r2dbc.io/spec/0.8.3.RELEASE/api/")
 		}
@@ -127,6 +130,8 @@ task extractDocResources(type: Copy, dependsOn: downloadResources) {
 }

 asciidoctorj {
+	def docRoot = 'https://docs.spring.io'
+	def docsSpringFramework = "${docRoot}/spring-framework/docs/${project.version}"
 	version = '2.4.1'
 	fatalWarnings ".*"
 	options doctype: 'book', eruby: 'erubis'
@@ -143,7 +148,11 @@ asciidoctorj {
 			'highlightjs-theme': 'googlecode',
 			stylesdir: 'css/',
 			stylesheet: 'stylesheet.css',
-			'spring-version': project.version
+			'spring-version': project.version,
+			'spring-framework-main-code': 'https://github.com/spring-projects/spring-framework/tree/main',
+			'doc-root': docRoot,
+			'docs-spring-framework': docsSpringFramework,
+			'api-spring-framework': "${docsSpringFramework}/javadoc-api/org/springframework"
 	])
 }

@@ -154,6 +163,9 @@ asciidoctorj {
 asciidoctor {
 	baseDirFollowsSourceDir()
 	configurations 'asciidoctorExt'
+	attributes([
+			noheader: '' // custom header in docinfo-header.html
+	])
 	sources {
 		include '*.adoc'
 	}
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2020 the original author or authors.
+ * Copyright 2002-2021 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
@@ -625,7 +625,7 @@ public class AspectJAdviceParameterNameDiscoverer implements ParameterNameDiscov
 			StringBuilder sb = new StringBuilder();
 			if (bodyStart >= 0 && bodyStart != (currentToken.length() - 1)) {
 				sb.append(currentToken.substring(bodyStart + 1));
-				sb.append(" ");
+				sb.append(' ');
 			}
 			numTokensConsumed++;
 			int currentIndex = startIndex + numTokensConsumed;
@@ -645,7 +645,7 @@ public class AspectJAdviceParameterNameDiscoverer implements ParameterNameDiscov
 					toAppend = toAppend.substring(1);
 				}
 				sb.append(toAppend);
-				sb.append(" ");
+				sb.append(' ');
 				currentIndex++;
 				numTokensConsumed++;
 			}
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2021 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
@@ -547,7 +547,7 @@ public class AspectJExpressionPointcut extends AbstractExpressionPointcut
 		StringBuilder sb = new StringBuilder("AspectJExpressionPointcut: (");
 		for (int i = 0; i < this.pointcutParameterTypes.length; i++) {
 			sb.append(this.pointcutParameterTypes[i].getName());
-			sb.append(" ");
+			sb.append(' ');
 			sb.append(this.pointcutParameterNames[i]);
 			if ((i+1) < this.pointcutParameterTypes.length) {
 				sb.append(", ");
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2020 the original author or authors.
+ * Copyright 2002-2021 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
@@ -255,19 +255,19 @@ public class MethodInvocationProceedingJoinPoint implements ProceedingJoinPoint,
 			StringBuilder sb = new StringBuilder();
 			if (includeModifier) {
 				sb.append(Modifier.toString(getModifiers()));
-				sb.append(" ");
+				sb.append(' ');
 			}
 			if (includeReturnTypeAndArgs) {
 				appendType(sb, getReturnType(), useLongReturnAndArgumentTypeName);
-				sb.append(" ");
+				sb.append(' ');
 			}
 			appendType(sb, getDeclaringType(), useLongTypeName);
-			sb.append(".");
+			sb.append('.');
 			sb.append(getMethod().getName());
-			sb.append("(");
+			sb.append('(');
 			Class<?>[] parametersTypes = getParameterTypes();
 			appendTypes(sb, parametersTypes, includeReturnTypeAndArgs, useLongReturnAndArgumentTypeName);
-			sb.append(")");
+			sb.append(')');
 			return sb.toString();
 		}

@@ -278,7 +278,7 @@ public class MethodInvocationProceedingJoinPoint implements ProceedingJoinPoint,
 				for (int size = types.length, i = 0; i < size; i++) {
 					appendType(sb, types[i], useLongReturnAndArgumentTypeName);
 					if (i < size - 1) {
-						sb.append(",");
+						sb.append(',');
 					}
 				}
 			}
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2020 the original author or authors.
+ * Copyright 2002-2021 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
@@ -19,7 +19,9 @@ package org.springframework.aop.framework;
 import java.lang.reflect.Array;
 import java.lang.reflect.Method;
 import java.lang.reflect.Proxy;
+import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.List;

 import org.springframework.aop.SpringProxy;
 import org.springframework.aop.TargetClassAware;
@@ -29,7 +31,9 @@ import org.springframework.aop.target.SingletonTargetSource;
 import org.springframework.core.DecoratingProxy;
 import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
+import org.springframework.util.ClassUtils;
 import org.springframework.util.ObjectUtils;
+import org.springframework.util.ReflectionUtils;

 /**
 * Utility methods for AOP proxy factories.
@@ -44,6 +48,11 @@ import org.springframework.util.ObjectUtils;
 */
 public abstract class AopProxyUtils {

+	// JDK 17 Class.isSealed() method available?
+	@Nullable
+	private static final Method isSealedMethod = ClassUtils.getMethodIfAvailable(Class.class, "isSealed");
+
+
 	/**
 	 * Obtain the singleton target object behind the given proxy, if any.
 	 * @param candidate the (potential) proxy to check
@@ -130,34 +139,23 @@ public abstract class AopProxyUtils {
 				specifiedInterfaces = advised.getProxiedInterfaces();
 			}
 		}
-		boolean addSpringProxy = !advised.isInterfaceProxied(SpringProxy.class);
-		boolean addAdvised = !advised.isOpaque() && !advised.isInterfaceProxied(Advised.class);
-		boolean addDecoratingProxy = (decoratingProxy && !advised.isInterfaceProxied(DecoratingProxy.class));
-		int nonUserIfcCount = 0;
-		if (addSpringProxy) {
-			nonUserIfcCount++;
+		List<Class<?>> proxiedInterfaces = new ArrayList<>(specifiedInterfaces.length + 3);
+		for (Class<?> ifc : specifiedInterfaces) {
+			// Only non-sealed interfaces are actually eligible for JDK proxying (on JDK 17)
+			if (isSealedMethod == null || Boolean.FALSE.equals(ReflectionUtils.invokeMethod(isSealedMethod, ifc))) {
+				proxiedInterfaces.add(ifc);
+			}
 		}
-		if (addAdvised) {
-			nonUserIfcCount++;
+		if (!advised.isInterfaceProxied(SpringProxy.class)) {
+			proxiedInterfaces.add(SpringProxy.class);
 		}
-		if (addDecoratingProxy) {
-			nonUserIfcCount++;
+		if (!advised.isOpaque() && !advised.isInterfaceProxied(Advised.class)) {
+			proxiedInterfaces.add(Advised.class);
 		}
-		Class<?>[] proxiedInterfaces = new Class<?>[specifiedInterfaces.length + nonUserIfcCount];
-		System.arraycopy(specifiedInterfaces, 0, proxiedInterfaces, 0, specifiedInterfaces.length);
-		int index = specifiedInterfaces.length;
-		if (addSpringProxy) {
-			proxiedInterfaces[index] = SpringProxy.class;
-			index++;
+		if (decoratingProxy && !advised.isInterfaceProxied(DecoratingProxy.class)) {
+			proxiedInterfaces.add(DecoratingProxy.class);
 		}
-		if (addAdvised) {
-			proxiedInterfaces[index] = Advised.class;
-			index++;
-		}
-		if (addDecoratingProxy) {
-			proxiedInterfaces[index] = DecoratingProxy.class;
-		}
-		return proxiedInterfaces;
+		return ClassUtils.toClassArray(proxiedInterfaces);
 	}

 	/**
@@ -17,6 +17,7 @@
 package org.springframework.aop.framework.autoproxy;

 import java.lang.reflect.Constructor;
+import java.lang.reflect.Proxy;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collections;
@@ -440,7 +441,17 @@ public abstract class AbstractAutoProxyCreator extends ProxyProcessorSupport
 		ProxyFactory proxyFactory = new ProxyFactory();
 		proxyFactory.copyFrom(this);

-		if (!proxyFactory.isProxyTargetClass()) {
+		if (proxyFactory.isProxyTargetClass()) {
+			// Explicit handling of JDK proxy targets (for introduction advice scenarios)
+			if (Proxy.isProxyClass(beanClass)) {
+				// Must allow for introductions; can't just set interfaces to the proxy's interfaces only.
+				for (Class<?> ifc : beanClass.getInterfaces()) {
+					proxyFactory.addInterface(ifc);
+				}
+			}
+		}
+		else {
+			// No proxyTargetClass flag enforced, let's apply our default checks...
 			if (shouldProxyTargetClass(beanClass, beanName)) {
 				proxyFactory.setProxyTargetClass(true);
 			}
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2017 the original author or authors.
+ * Copyright 2002-2021 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
@@ -137,7 +137,7 @@ public abstract class AbstractBeanFactoryPointcutAdvisor extends AbstractPointcu
 		StringBuilder sb = new StringBuilder(getClass().getName());
 		sb.append(": advice ");
 		if (this.adviceBeanName != null) {
-			sb.append("bean '").append(this.adviceBeanName).append("'");
+			sb.append("bean '").append(this.adviceBeanName).append('\'');
 		}
 		else {
 			sb.append(this.advice);
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2021 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
@@ -71,7 +71,8 @@ public class DefaultIntroductionAdvisor implements IntroductionAdvisor, ClassFil
 		if (introductionInfo != null) {
 			Class<?>[] introducedInterfaces = introductionInfo.getInterfaces();
 			if (introducedInterfaces.length == 0) {
-				throw new IllegalArgumentException("IntroductionAdviceSupport implements no interfaces");
+				throw new IllegalArgumentException(
+						"IntroductionInfo defines no interfaces to introduce: " + introductionInfo);
 			}
 			for (Class<?> ifc : introducedInterfaces) {
 				addInterface(ifc);
@@ -191,9 +191,9 @@ public abstract class AbstractBeanFactoryBasedTargetSource implements TargetSour
 	@Override
 	public String toString() {
 		StringBuilder sb = new StringBuilder(getClass().getSimpleName());
-		sb.append(" for target bean '").append(this.targetBeanName).append("'");
+		sb.append(" for target bean '").append(this.targetBeanName).append('\'');
 		if (this.targetClass != null) {
-			sb.append(" of type [").append(this.targetClass.getName()).append("]");
+			sb.append(" of type [").append(this.targetClass.getName()).append(']');
 		}
 		return sb.toString();
 	}
@@ -276,14 +276,14 @@ public class AspectJAdviceParameterNameDiscovererTests {

 	private static String format(String[] names) {
 		StringBuilder sb = new StringBuilder();
-		sb.append("(");
+		sb.append('(');
 		for (int i = 0; i < names.length; i++) {
 			sb.append(names[i]);
 			if ((i + 1) < names.length) {
-				sb.append(",");
+				sb.append(',');
 			}
 		}
-		sb.append(")");
+		sb.append(')');
 		return sb.toString();
 	}

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2021 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
@@ -183,7 +183,7 @@ public class ProxyFactoryTests {
 	}

 	@Test
-	public void testGetsAllInterfaces() throws Exception {
+	public void testGetsAllInterfaces() {
 		// Extend to get new interface
 		class TestBeanSubclass extends TestBean implements Comparable<Object> {
 			@Override
@@ -240,6 +240,16 @@ public class ProxyFactoryTests {
 		assertThat(factory.countAdvicesOfType(NopInterceptor.class) == 2).isTrue();
 	}

+	@Test
+	public void testSealedInterfaceExclusion() {
+		// String implements ConstantDesc on JDK 12+, sealed as of JDK 17
+		ProxyFactory factory = new ProxyFactory(new String());
+		NopInterceptor di = new NopInterceptor();
+		factory.addAdvice(0, di);
+		Object proxy = factory.getProxy();
+		assertThat(proxy).isInstanceOf(CharSequence.class);
+	}
+
 	/**
 	 * Should see effect immediately on behavior.
 	 */
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2020 the original author or authors.
+ * Copyright 2002-2021 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
@@ -41,8 +41,6 @@ import kotlin.reflect.KParameter;
 import kotlin.reflect.full.KClasses;
 import kotlin.reflect.jvm.KCallablesJvm;
 import kotlin.reflect.jvm.ReflectJvmMapping;
-import org.apache.commons.logging.Log;
-import org.apache.commons.logging.LogFactory;

 import org.springframework.core.DefaultParameterNameDiscoverer;
 import org.springframework.core.KotlinDetector;
@@ -75,8 +73,6 @@ import org.springframework.util.StringUtils;
 */
 public abstract class BeanUtils {

-	private static final Log logger = LogFactory.getLog(BeanUtils.class);
-
 	private static final ParameterNameDiscoverer parameterNameDiscoverer =
 			new DefaultParameterNameDiscoverer();

@@ -551,9 +547,6 @@ public abstract class BeanUtils {
 			}
 			catch (Throwable ex) {
 				// e.g. AccessControlException on Google App Engine
-				if (logger.isDebugEnabled()) {
-					logger.debug("Could not access system ClassLoader: " + ex);
-				}
 				return null;
 			}
 		}
@@ -564,10 +557,6 @@ public abstract class BeanUtils {
 			Class<?> editorClass = cl.loadClass(editorName);
 			if (editorClass != null) {
 				if (!PropertyEditor.class.isAssignableFrom(editorClass)) {
-					if (logger.isInfoEnabled()) {
-						logger.info("Editor class [" + editorName +
-								"] does not implement [java.beans.PropertyEditor] interface");
-					}
 					unknownEditorTypes.add(targetType);
 					return null;
 				}
@@ -579,10 +568,6 @@ public abstract class BeanUtils {
 		catch (ClassNotFoundException ex) {
 			// Ignore - fall back to unknown editor type registration below
 		}
-		if (logger.isTraceEnabled()) {
-			logger.trace("No property editor [" + editorName + "] found for type " +
-					targetTypeName + " according to 'Editor' suffix convention");
-		}
 		unknownEditorTypes.add(targetType);
 		return null;
 	}
@@ -247,14 +247,14 @@ class TypeConverterDelegate {
 				// Definitely doesn't match: throw IllegalArgumentException/IllegalStateException
 				StringBuilder msg = new StringBuilder();
 				msg.append("Cannot convert value of type '").append(ClassUtils.getDescriptiveType(newValue));
-				msg.append("' to required type '").append(ClassUtils.getQualifiedName(requiredType)).append("'");
+				msg.append("' to required type '").append(ClassUtils.getQualifiedName(requiredType)).append('\'');
 				if (propertyName != null) {
-					msg.append(" for property '").append(propertyName).append("'");
+					msg.append(" for property '").append(propertyName).append('\'');
 				}
 				if (editor != null) {
 					msg.append(": PropertyEditor [").append(editor.getClass().getName()).append(
 							"] returned inappropriate value of type '").append(
-							ClassUtils.getDescriptiveType(convertedValue)).append("'");
+							ClassUtils.getDescriptiveType(convertedValue)).append('\'');
 					throw new IllegalArgumentException(msg.toString());
 				}
 				else {
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2020 the original author or authors.
+ * Copyright 2002-2021 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
@@ -84,7 +84,7 @@ import org.springframework.lang.Nullable;
 * (only applicable when running in a web application context)
 * <li>{@code postProcessBeforeInitialization} methods of BeanPostProcessors
 * <li>InitializingBean's {@code afterPropertiesSet}
- * <li>a custom init-method definition
+ * <li>a custom {@code init-method} definition
 * <li>{@code postProcessAfterInitialization} methods of BeanPostProcessors
 * </ol>
 *
@@ -92,7 +92,7 @@ import org.springframework.lang.Nullable;
 * <ol>
 * <li>{@code postProcessBeforeDestruction} methods of DestructionAwareBeanPostProcessors
 * <li>DisposableBean's {@code destroy}
- * <li>a custom destroy-method definition
+ * <li>a custom {@code destroy-method} definition
 * </ol>
 *
 * @author Rod Johnson
@@ -102,6 +102,8 @@ import org.springframework.lang.Nullable;
 * @see BeanNameAware#setBeanName
 * @see BeanClassLoaderAware#setBeanClassLoader
 * @see BeanFactoryAware#setBeanFactory
+ * @see org.springframework.context.EnvironmentAware#setEnvironment
+ * @see org.springframework.context.EmbeddedValueResolverAware#setEmbeddedValueResolver
 * @see org.springframework.context.ResourceLoaderAware#setResourceLoader
 * @see org.springframework.context.ApplicationEventPublisherAware#setApplicationEventPublisher
 * @see org.springframework.context.MessageSourceAware#setMessageSource
@@ -111,6 +113,7 @@ import org.springframework.lang.Nullable;
 * @see InitializingBean#afterPropertiesSet
 * @see org.springframework.beans.factory.support.RootBeanDefinition#getInitMethodName
 * @see org.springframework.beans.factory.config.BeanPostProcessor#postProcessAfterInitialization
+ * @see org.springframework.beans.factory.config.DestructionAwareBeanPostProcessor#postProcessBeforeDestruction
 * @see DisposableBean#destroy
 * @see org.springframework.beans.factory.support.RootBeanDefinition#getDestroyMethodName
 */
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2020 the original author or authors.
+ * Copyright 2002-2021 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
@@ -217,13 +217,13 @@ public class RequiredAnnotationBeanPostProcessor implements SmartInstantiationAw
 					sb.append(" and");
 				}
 				else {
-					sb.append(",");
+					sb.append(',');
 				}
 			}
-			sb.append(" '").append(propertyName).append("'");
+			sb.append(" '").append(propertyName).append('\'');
 		}
 		sb.append(size == 1 ? " is" : " are");
-		sb.append(" required for bean '").append(beanName).append("'");
+		sb.append(" required for bean '").append(beanName).append('\'');
 		return sb.toString();
 	}

@@ -489,9 +489,9 @@ public class GroovyBeanDefinitionReader extends AbstractBeanDefinitionReader imp
 						resolveConstructorArguments(args, 2, hasClosureArgument ? args.length - 1 : args.length);
 				this.currentBeanDefinition = new GroovyBeanDefinitionWrapper(beanName, (Class<?>) args[1], constructorArgs);
 				Map<?, ?> namedArgs = (Map<?, ?>) args[0];
-				for (Object key : namedArgs.keySet()) {
-					String propName = (String) key;
-					setProperty(propName, namedArgs.get(propName));
+				for (Map.Entry<?, ?> entity : namedArgs.entrySet()) {
+					String propName = (String) entity.getKey();
+					setProperty(propName, entity.getValue());
 				}
 			}
 			// factory method syntax
@@ -1241,7 +1241,7 @@ public abstract class AbstractBeanDefinition extends BeanMetadataAttributeAccess
 	@Override
 	public String toString() {
 		StringBuilder sb = new StringBuilder("class [");
-		sb.append(getBeanClassName()).append("]");
+		sb.append(getBeanClassName()).append(']');
 		sb.append("; scope=").append(this.scope);
 		sb.append("; abstract=").append(this.abstractFlag);
 		sb.append("; lazyInit=").append(this.lazyInit);
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2021 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
@@ -21,6 +21,7 @@ import java.util.function.Supplier;
 import org.springframework.beans.factory.config.AutowiredPropertyMarker;
 import org.springframework.beans.factory.config.BeanDefinitionCustomizer;
 import org.springframework.beans.factory.config.RuntimeBeanReference;
+import org.springframework.core.ResolvableType;
 import org.springframework.lang.Nullable;
 import org.springframework.util.ObjectUtils;

@@ -102,7 +103,7 @@ public final class BeanDefinitionBuilder {
 	 * @param beanClass the {@code Class} of the bean that the definition is being created for
 	 */
 	public static BeanDefinitionBuilder rootBeanDefinition(Class<?> beanClass) {
-		return rootBeanDefinition(beanClass, null);
+		return rootBeanDefinition(beanClass, (String) null);
 	}

 	/**
@@ -117,6 +118,30 @@ public final class BeanDefinitionBuilder {
 		return builder;
 	}

+	/**
+	 * Create a new {@code BeanDefinitionBuilder} used to construct a {@link RootBeanDefinition}.
+	 * @param beanType the {@link ResolvableType type} of the bean that the definition is being created for
+	 * @param instanceSupplier a callback for creating an instance of the bean
+	 * @since 5.3.9
+	 */
+	public static <T> BeanDefinitionBuilder rootBeanDefinition(ResolvableType beanType, Supplier<T> instanceSupplier) {
+		RootBeanDefinition beanDefinition = new RootBeanDefinition();
+		beanDefinition.setTargetType(beanType);
+		beanDefinition.setInstanceSupplier(instanceSupplier);
+		return new BeanDefinitionBuilder(beanDefinition);
+	}
+
+	/**
+	 * Create a new {@code BeanDefinitionBuilder} used to construct a {@link RootBeanDefinition}.
+	 * @param beanClass the {@code Class} of the bean that the definition is being created for
+	 * @param instanceSupplier a callback for creating an instance of the bean
+	 * @since 5.3.9
+	 * @see #rootBeanDefinition(ResolvableType, Supplier)
+	 */
+	public static <T> BeanDefinitionBuilder rootBeanDefinition(Class<T> beanClass, Supplier<T> instanceSupplier) {
+		return rootBeanDefinition(ResolvableType.forClass(beanClass), instanceSupplier);
+	}
+
 	/**
 	 * Create a new {@code BeanDefinitionBuilder} used to construct a {@link ChildBeanDefinition}.
 	 * @param parentName the name of the parent bean
@@ -331,6 +356,16 @@ public final class BeanDefinitionBuilder {
 		return this;
 	}

+	/**
+	 * Set whether this bean is 'synthetic', that is, not defined by
+	 * the application itself.
+	 * @since 5.3.9
+	 */
+	public BeanDefinitionBuilder setSynthetic(boolean synthetic) {
+		this.beanDefinition.setSynthetic(synthetic);
+		return this;
+	}
+
 	/**
 	 * Apply the given customizers to the underlying bean definition.
 	 * @since 5.0
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2020 the original author or authors.
+ * Copyright 2002-2021 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
@@ -35,6 +35,7 @@ import org.springframework.cglib.proxy.Factory;
 import org.springframework.cglib.proxy.MethodInterceptor;
 import org.springframework.cglib.proxy.MethodProxy;
 import org.springframework.cglib.proxy.NoOp;
+import org.springframework.core.ResolvableType;
 import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 import org.springframework.util.StringUtils;
@@ -244,8 +245,10 @@ public class CglibSubclassingInstantiationStrategy extends SimpleInstantiationSt
 				return (bean.equals(null) ? null : bean);
 			}
 			else {
-				return (argsToUse != null ? this.owner.getBean(method.getReturnType(), argsToUse) :
-						this.owner.getBean(method.getReturnType()));
+				// Find target bean matching the (potentially generic) method return type
+				ResolvableType genericReturnType = ResolvableType.forMethodReturnType(method);
+				return (argsToUse != null ? this.owner.getBeanProvider(genericReturnType).getObject(argsToUse) :
+						this.owner.getBeanProvider(genericReturnType).getObject());
 			}
 		}
 	}
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2020 the original author or authors.
+ * Copyright 2002-2021 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
@@ -277,12 +277,12 @@ class ConstructorResolver {
 					throw ex;
 				}
 				throw new BeanCreationException(mbd.getResourceDescription(), beanName,
-						"Could not resolve matching constructor " +
+						"Could not resolve matching constructor on bean class [" + mbd.getBeanClassName() + "] " +
 						"(hint: specify index/type/name arguments for simple parameters to avoid type ambiguities)");
 			}
 			else if (ambiguousConstructors != null && !mbd.isLenientConstructorResolution()) {
 				throw new BeanCreationException(mbd.getResourceDescription(), beanName,
-						"Ambiguous constructor matches found in bean '" + beanName + "' " +
+						"Ambiguous constructor matches found on bean class [" + mbd.getBeanClassName() + "] " +
 						"(hint: specify index/type/name arguments for simple parameters to avoid type ambiguities): " +
 						ambiguousConstructors);
 			}
@@ -608,7 +608,7 @@ class ConstructorResolver {
 				}
 				String argDesc = StringUtils.collectionToCommaDelimitedString(argTypes);
 				throw new BeanCreationException(mbd.getResourceDescription(), beanName,
-						"No matching factory method found: " +
+						"No matching factory method found on class [" + factoryClass.getName() + "]: " +
 						(mbd.getFactoryBeanName() != null ?
 							"factory bean '" + mbd.getFactoryBeanName() + "'; " : "") +
 						"factory method '" + mbd.getFactoryMethodName() + "(" + argDesc + ")'. " +
@@ -619,12 +619,12 @@ class ConstructorResolver {
 			}
 			else if (void.class == factoryMethodToUse.getReturnType()) {
 				throw new BeanCreationException(mbd.getResourceDescription(), beanName,
-						"Invalid factory method '" + mbd.getFactoryMethodName() +
-						"': needs to have a non-void return type!");
+						"Invalid factory method '" + mbd.getFactoryMethodName() + "' on class [" +
+						factoryClass.getName() + "]: needs to have a non-void return type!");
 			}
 			else if (ambiguousFactoryMethods != null) {
 				throw new BeanCreationException(mbd.getResourceDescription(), beanName,
-						"Ambiguous factory method matches found in bean '" + beanName + "' " +
+						"Ambiguous factory method matches found on class [" + factoryClass.getName() + "] " +
 						"(hint: specify index/type/name arguments for simple parameters to avoid type ambiguities): " +
 						ambiguousFactoryMethods);
 			}
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2017 the original author or authors.
+ * Copyright 2002-2021 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
@@ -19,17 +19,25 @@ package org.springframework.beans.factory.support;
 import java.lang.reflect.Method;
 import java.lang.reflect.Modifier;

+import org.springframework.core.ResolvableType;
 import org.springframework.lang.Nullable;
 import org.springframework.util.ObjectUtils;

 /**
- * Represents an override of a method that looks up an object in the same IoC context.
+ * Represents an override of a method that looks up an object in the same IoC context,
+ * either by bean name or by bean type (based on the declared method return type).
 *
- * <p>Methods eligible for lookup override must not have arguments.
+ * <p>Methods eligible for lookup override may declare arguments in which case the
+ * given arguments are passed to the bean retrieval operation.
 *
 * @author Rod Johnson
 * @author Juergen Hoeller
 * @since 1.1
+ * @see org.springframework.beans.factory.BeanFactory#getBean(String)
+ * @see org.springframework.beans.factory.BeanFactory#getBean(Class)
+ * @see org.springframework.beans.factory.BeanFactory#getBean(String, Object...)
+ * @see org.springframework.beans.factory.BeanFactory#getBean(Class, Object...)
+ * @see org.springframework.beans.factory.BeanFactory#getBeanProvider(ResolvableType)
 */
 public class LookupOverride extends MethodOverride {

@@ -43,8 +51,8 @@ public class LookupOverride extends MethodOverride {
 	/**
 	 * Construct a new LookupOverride.
 	 * @param methodName the name of the method to override
-	 * @param beanName the name of the bean in the current {@code BeanFactory}
-	 * that the overridden method should return (may be {@code null})
+	 * @param beanName the name of the bean in the current {@code BeanFactory} that the
+	 * overridden method should return (may be {@code null} for type-based bean retrieval)
 	 */
 	public LookupOverride(String methodName, @Nullable String beanName) {
 		super(methodName);
@@ -53,9 +61,9 @@ public class LookupOverride extends MethodOverride {

 	/**
 	 * Construct a new LookupOverride.
-	 * @param method the method to override
-	 * @param beanName the name of the bean in the current {@code BeanFactory}
-	 * that the overridden method should return (may be {@code null})
+	 * @param method the method declaration to override
+	 * @param beanName the name of the bean in the current {@code BeanFactory} that the
+	 * overridden method should return (may be {@code null} for type-based bean retrieval)
 	 */
 	public LookupOverride(Method method, @Nullable String beanName) {
 		super(method.getName());
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2012 the original author or authors.
+ * Copyright 2002-2021 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
@@ -19,9 +19,8 @@ package org.springframework.beans.factory.support;
 import java.lang.reflect.Method;

 /**
- * Interface to be implemented by classes that can reimplement any method
- * on an IoC-managed object: the <b>Method Injection</b> form of
- * Dependency Injection.
+ * Interface to be implemented by classes that can reimplement any method on an
+ * IoC-managed object: the <b>Method Injection</b> form of Dependency Injection.
 *
 * <p>Such methods may be (but need not be) abstract, in which case the
 * container will create a concrete subclass to instantiate.
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2020 the original author or authors.
+ * Copyright 2002-2021 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
@@ -25,7 +25,7 @@ import org.springframework.util.Assert;
 import org.springframework.util.ObjectUtils;

 /**
- * Extension of MethodOverride that represents an arbitrary
+ * Extension of {@link MethodOverride} that represents an arbitrary
 * override of a method by the IoC container.
 *
 * <p>Any non-final method can be overridden, irrespective of its
@@ -45,7 +45,7 @@ public class ReplaceOverride extends MethodOverride {
 	/**
 	 * Construct a new ReplaceOverride.
 	 * @param methodName the name of the method to override
-	 * @param methodReplacerBeanName the bean name of the MethodReplacer
+	 * @param methodReplacerBeanName the bean name of the {@link MethodReplacer}
 	 */
 	public ReplaceOverride(String methodName, String methodReplacerBeanName) {
 		super(methodName);
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2021 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
@@ -18,14 +18,14 @@ package org.springframework.beans;

 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
-import java.util.Collections;
-import java.util.HashSet;
 import java.util.Iterator;
 import java.util.Properties;
 import java.util.Set;
+import java.util.concurrent.ConcurrentHashMap;

 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
+import org.junit.jupiter.api.RepeatedTest;
 import org.junit.jupiter.api.Test;

 import static org.assertj.core.api.Assertions.assertThat;
@@ -36,23 +36,21 @@ import static org.assertj.core.api.Assertions.assertThat;
 * @author Chris Beams
 * @since 08.03.2004
 */
-public class ConcurrentBeanWrapperTests {
+class ConcurrentBeanWrapperTests {

 	private final Log logger = LogFactory.getLog(getClass());

-	private Set<TestRun> set = Collections.synchronizedSet(new HashSet<TestRun>());
+	private final Set<TestRun> set = ConcurrentHashMap.newKeySet();

 	private Throwable ex = null;

-	@Test
-	public void testSingleThread() {
-		for (int i = 0; i < 100; i++) {
-			performSet();
-		}
+	@RepeatedTest(100)
+	void testSingleThread() {
+		performSet();
 	}

 	@Test
-	public void testConcurrent() {
+	void testConcurrent() {
 		for (int i = 0; i < 10; i++) {
 			TestRun run = new TestRun(this);
 			set.add(run);
@@ -82,7 +80,7 @@ public class ConcurrentBeanWrapperTests {

 		Properties p = (Properties) System.getProperties().clone();

-		assertThat(p.size() != 0).as("The System properties must not be empty").isTrue();
+		assertThat(p).as("The System properties must not be empty").isNotEmpty();

 		for (Iterator<?> i = p.entrySet().iterator(); i.hasNext();) {
 			i.next();
@@ -111,7 +109,7 @@ public class ConcurrentBeanWrapperTests {

 		private ConcurrentBeanWrapperTests test;

-		public TestRun(ConcurrentBeanWrapperTests test) {
+		TestRun(ConcurrentBeanWrapperTests test) {
 			this.test = test;
 		}

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2021 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
@@ -31,6 +31,7 @@ import static org.springframework.beans.factory.support.BeanDefinitionBuilder.ro
 * invoking a factory method is not instructive to the user and rather misleading.
 *
 * @author Chris Beams
+ * @author Juergen Hoeller
 */
 public class Spr5475Tests {

@@ -40,7 +41,8 @@ public class Spr5475Tests {
 				rootBeanDefinition(Foo.class)
 					.setFactoryMethod("noArgFactory")
 					.addConstructorArgValue("bogusArg").getBeanDefinition(),
-				"Error creating bean with name 'foo': No matching factory method found: factory method 'noArgFactory(String)'. " +
+				"Error creating bean with name 'foo': No matching factory method found on class " +
+				"[org.springframework.beans.factory.Spr5475Tests$Foo]: factory method 'noArgFactory(String)'. " +
 				"Check that a method with the specified name and arguments exists and that it is static.");
 	}

@@ -51,7 +53,8 @@ public class Spr5475Tests {
 					.setFactoryMethod("noArgFactory")
 					.addConstructorArgValue("bogusArg1")
 					.addConstructorArgValue("bogusArg2".getBytes()).getBeanDefinition(),
-				"Error creating bean with name 'foo': No matching factory method found: factory method 'noArgFactory(String,byte[])'. " +
+				"Error creating bean with name 'foo': No matching factory method found on class " +
+				"[org.springframework.beans.factory.Spr5475Tests$Foo]: factory method 'noArgFactory(String,byte[])'. " +
 				"Check that a method with the specified name and arguments exists and that it is static.");
 	}

@@ -65,7 +68,8 @@ public class Spr5475Tests {
 		def.setConstructorArgumentValues(cav);

 		assertExceptionMessageForMisconfiguredFactoryMethod(def,
-				"Error creating bean with name 'foo': No matching factory method found: factory method 'noArgFactory(CharSequence,byte[])'. " +
+				"Error creating bean with name 'foo': No matching factory method found on class " +
+				"[org.springframework.beans.factory.Spr5475Tests$Foo]: factory method 'noArgFactory(CharSequence,byte[])'. " +
 				"Check that a method with the specified name and arguments exists and that it is static.");
 	}

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2020 the original author or authors.
+ * Copyright 2002-2021 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
@@ -121,6 +121,18 @@ public class LookupAnnotationTests {
 		assertThat(beanFactory.getBean(BeanConsumer.class).abstractBean).isSameAs(bean);
 	}

+	@Test
+	public void testWithGenericBean() {
+		beanFactory.registerBeanDefinition("numberBean", new RootBeanDefinition(NumberBean.class));
+		beanFactory.registerBeanDefinition("doubleStore", new RootBeanDefinition(DoubleStore.class));
+		beanFactory.registerBeanDefinition("floatStore", new RootBeanDefinition(FloatStore.class));
+
+		NumberBean bean = (NumberBean) beanFactory.getBean("numberBean");
+		assertThat(bean).isNotNull();
+		assertThat(beanFactory.getBean(DoubleStore.class)).isSameAs(bean.getDoubleStore());
+		assertThat(beanFactory.getBean(FloatStore.class)).isSameAs(bean.getFloatStore());
+	}
+

 	public static abstract class AbstractBean {

@@ -147,4 +159,26 @@ public class LookupAnnotationTests {
 		AbstractBean abstractBean;
 	}

+
+	public static class NumberStore<T extends Number> {
+	}
+
+
+	public static class DoubleStore extends NumberStore<Double> {
+	}
+
+
+	public static class FloatStore extends NumberStore<Float> {
+	}
+
+
+	public static abstract class NumberBean {
+
+		@Lookup
+		public abstract NumberStore<Double> getDoubleStore();
+
+		@Lookup
+		public abstract NumberStore<Float> getFloatStore();
+	}
+
 }
@@ -141,6 +141,7 @@ class YamlProcessorTests {
 	}

 	@Test
+	@SuppressWarnings("unchecked")
 	void standardTypesSupportedByDefault() throws Exception {
 		setYaml("value: !!set\n  ? first\n  ? second");
 		this.processor.process((properties, map) -> {
@@ -17,22 +17,25 @@
 package org.springframework.beans.factory.support;

 import java.util.Arrays;
+import java.util.function.Function;

 import org.junit.jupiter.api.Test;

 import org.springframework.beans.factory.config.BeanDefinition;
 import org.springframework.beans.testfixture.beans.TestBean;
+import org.springframework.core.ResolvableType;

 import static org.assertj.core.api.Assertions.assertThat;

 /**
 * @author Rod Johnson
 * @author Juergen Hoeller
+ * @author Stephane Nicoll
 */
-public class BeanDefinitionBuilderTests {
+class BeanDefinitionBuilderTests {

 	@Test
-	public void beanClassWithSimpleProperty() {
+	void builderWithBeanClassWithSimpleProperty() {
 		String[] dependsOn = new String[] { "A", "B", "C" };
 		BeanDefinitionBuilder bdb = BeanDefinitionBuilder.rootBeanDefinition(TestBean.class);
 		bdb.setScope(BeanDefinition.SCOPE_PROTOTYPE);
@@ -49,7 +52,7 @@ public class BeanDefinitionBuilderTests {
 	}

 	@Test
-	public void beanClassWithFactoryMethod() {
+	void builderWithBeanClassAndFactoryMethod() {
 		BeanDefinitionBuilder bdb = BeanDefinitionBuilder.rootBeanDefinition(TestBean.class, "create");
 		RootBeanDefinition rbd = (RootBeanDefinition) bdb.getBeanDefinition();
 		assertThat(rbd.hasBeanClass()).isTrue();
@@ -58,7 +61,7 @@ public class BeanDefinitionBuilderTests {
 	}

 	@Test
-	public void beanClassName() {
+	void builderWithBeanClassName() {
 		BeanDefinitionBuilder bdb = BeanDefinitionBuilder.rootBeanDefinition(TestBean.class.getName());
 		RootBeanDefinition rbd = (RootBeanDefinition) bdb.getBeanDefinition();
 		assertThat(rbd.hasBeanClass()).isFalse();
@@ -66,7 +69,7 @@ public class BeanDefinitionBuilderTests {
 	}

 	@Test
-	public void beanClassNameWithFactoryMethod() {
+	void builderWithBeanClassNameAndFactoryMethod() {
 		BeanDefinitionBuilder bdb = BeanDefinitionBuilder.rootBeanDefinition(TestBean.class.getName(), "create");
 		RootBeanDefinition rbd = (RootBeanDefinition) bdb.getBeanDefinition();
 		assertThat(rbd.hasBeanClass()).isFalse();
@@ -74,4 +77,78 @@ public class BeanDefinitionBuilderTests {
 		assertThat(rbd.getFactoryMethodName()).isEqualTo("create");
 	}

+	@Test
+	void builderWithResolvableTypeAndInstanceSupplier() {
+		ResolvableType type = ResolvableType.forClassWithGenerics(Function.class, Integer.class, String.class);
+		Function<Integer, String> function = i -> "value " + i;
+		RootBeanDefinition rbd = (RootBeanDefinition) BeanDefinitionBuilder
+				.rootBeanDefinition(type, () -> function).getBeanDefinition();
+		assertThat(rbd.getResolvableType()).isEqualTo(type);
+		assertThat(rbd.getInstanceSupplier()).isNotNull();
+		assertThat(rbd.getInstanceSupplier().get()).isInstanceOf(Function.class);
+	}
+
+	@Test
+	void builderWithBeanClassAndInstanceSupplier() {
+		RootBeanDefinition rbd = (RootBeanDefinition) BeanDefinitionBuilder
+				.rootBeanDefinition(String.class, () -> "test").getBeanDefinition();
+		assertThat(rbd.getResolvableType().resolve()).isEqualTo(String.class);
+		assertThat(rbd.getInstanceSupplier()).isNotNull();
+		assertThat(rbd.getInstanceSupplier().get()).isEqualTo("test");
+	}
+
+	@Test
+	void builderWithAutowireMode() {
+		assertThat(BeanDefinitionBuilder.rootBeanDefinition(TestBean.class)
+				.setAutowireMode(RootBeanDefinition.AUTOWIRE_BY_TYPE).getBeanDefinition().getAutowireMode())
+				.isEqualTo(RootBeanDefinition.AUTOWIRE_BY_TYPE);
+	}
+
+	@Test
+	void builderWithDependencyCheck() {
+		assertThat(BeanDefinitionBuilder.rootBeanDefinition(TestBean.class)
+				.setDependencyCheck(RootBeanDefinition.DEPENDENCY_CHECK_ALL)
+				.getBeanDefinition().getDependencyCheck())
+				.isEqualTo(RootBeanDefinition.DEPENDENCY_CHECK_ALL);
+	}
+
+	@Test
+	void builderWithDependsOn() {
+		assertThat(BeanDefinitionBuilder.rootBeanDefinition(TestBean.class).addDependsOn("test")
+				.addDependsOn("test2").getBeanDefinition().getDependsOn())
+				.containsExactly("test", "test2");
+	}
+
+	@Test
+	void builderWithPrimary() {
+		assertThat(BeanDefinitionBuilder.rootBeanDefinition(TestBean.class)
+				.setPrimary(true).getBeanDefinition().isPrimary()).isTrue();
+	}
+
+	@Test
+	void builderWithRole() {
+		assertThat(BeanDefinitionBuilder.rootBeanDefinition(TestBean.class)
+				.setRole(BeanDefinition.ROLE_INFRASTRUCTURE).getBeanDefinition().getRole())
+				.isEqualTo(BeanDefinition.ROLE_INFRASTRUCTURE);
+	}
+
+	@Test
+	void builderWithSynthetic() {
+		assertThat(BeanDefinitionBuilder.rootBeanDefinition(TestBean.class)
+				.setSynthetic(true).getBeanDefinition().isSynthetic()).isTrue();
+	}
+
+	@Test
+	void builderWithCustomizers() {
+		BeanDefinition beanDefinition = BeanDefinitionBuilder.rootBeanDefinition(TestBean.class)
+				.applyCustomizers(builder -> {
+					builder.setFactoryMethodName("create");
+					builder.setRole(BeanDefinition.ROLE_SUPPORT);
+				})
+				.applyCustomizers(builder -> builder.setRole(BeanDefinition.ROLE_INFRASTRUCTURE))
+				.getBeanDefinition();
+		assertThat(beanDefinition.getFactoryMethodName()).isEqualTo("create");
+		assertThat(beanDefinition.getRole()).isEqualTo(BeanDefinition.ROLE_INFRASTRUCTURE);
+	}
+
 }
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2021 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
@@ -36,7 +36,7 @@ public class LookupMethodTests {


 	@BeforeEach
-	public void setUp() {
+	public void setup() {
 		beanFactory = new DefaultListableBeanFactory();
 		XmlBeanDefinitionReader reader = new XmlBeanDefinitionReader(beanFactory);
 		reader.loadBeanDefinitions(new ClassPathResource("lookupMethodTests.xml", getClass()));
@@ -83,8 +83,8 @@ public class LookupMethodTests {
 	public void testWithThreeArgsShouldFail() {
 		AbstractBean bean = (AbstractBean) beanFactory.getBean("abstractBean");
 		assertThat(bean).isNotNull();
-		assertThatExceptionOfType(AbstractMethodError.class).as("does not have a three arg constructor").isThrownBy(() ->
-			bean.getThreeArguments("name", 1, 2));
+		assertThatExceptionOfType(AbstractMethodError.class).as("does not have a three arg constructor")
+				.isThrownBy(() -> bean.getThreeArguments("name", 1, 2));
 	}

 	@Test
@@ -97,6 +97,21 @@ public class LookupMethodTests {
 		assertThat(expected.isJedi()).isTrue();
 	}

+	@Test
+	public void testWithGenericBean() {
+		RootBeanDefinition bd = new RootBeanDefinition(NumberBean.class);
+		bd.getMethodOverrides().addOverride(new LookupOverride("getDoubleStore", null));
+		bd.getMethodOverrides().addOverride(new LookupOverride("getFloatStore", null));
+		beanFactory.registerBeanDefinition("numberBean", bd);
+		beanFactory.registerBeanDefinition("doubleStore", new RootBeanDefinition(DoubleStore.class));
+		beanFactory.registerBeanDefinition("floatStore", new RootBeanDefinition(FloatStore.class));
+
+		NumberBean bean = (NumberBean) beanFactory.getBean("numberBean");
+		assertThat(bean).isNotNull();
+		assertThat(beanFactory.getBean(DoubleStore.class)).isSameAs(bean.getDoubleStore());
+		assertThat(beanFactory.getBean(FloatStore.class)).isSameAs(bean.getFloatStore());
+	}
+

 	public static abstract class AbstractBean {

@@ -111,4 +126,24 @@ public class LookupMethodTests {
 		public abstract TestBean getThreeArguments(String name, int age, int anotherArg);
 	}

+
+	public static class NumberStore<T extends Number> {
+	}
+
+
+	public static class DoubleStore extends NumberStore<Double> {
+	}
+
+
+	public static class FloatStore extends NumberStore<Float> {
+	}
+
+
+	public static abstract class NumberBean {
+
+		public abstract NumberStore<Double> getDoubleStore();
+
+		public abstract NumberStore<Float> getFloatStore();
+	}
+
 }
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2021 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
@@ -244,7 +244,7 @@ public class QualifierAnnotationAutowireBeanFactoryTests {
 	@Target({ElementType.FIELD, ElementType.PARAMETER})
 	@Retention(RetentionPolicy.RUNTIME)
 	@Qualifier
-	private static @interface TestQualifier {
+	private @interface TestQualifier {
 	}

 }
@@ -36,7 +36,7 @@ import javax.lang.model.element.Modifier;
 import javax.lang.model.element.TypeElement;

 /**
- * Annotation {@link Processor} that writes {@link CandidateComponentsMetadata}
+ * Annotation {@link Processor} that writes a {@link CandidateComponentsMetadata}
 * file for spring components.
 *
 * @author Stephane Nicoll
@@ -26,7 +26,7 @@ import javax.lang.model.element.ElementKind;

 /**
 * A {@link StereotypesProvider} implementation that extracts the stereotypes
- * flagged by the {@value INDEXED_ANNOTATION} annotation. This implementation
+ * flagged by the {@value #INDEXED_ANNOTATION} annotation. This implementation
 * honors stereotypes defined this way on meta-annotations.
 *
 * @author Stephane Nicoll
@@ -24,7 +24,7 @@ import javax.lang.model.element.ElementKind;

 /**
 * A {@link StereotypesProvider} implementation that provides the
- * {@value STEREOTYPE} stereotype for each package-info.
+ * {@value #STEREOTYPE} stereotype for each package-info.
 *
 * @author Stephane Nicoll
 * @since 5.0
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2021 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
@@ -24,8 +24,8 @@ import javax.lang.model.element.Element;
 import javax.lang.model.element.ElementKind;

 /**
- * A {@link StereotypesProvider} that extract a stereotype for each
- * {@code javax.*} annotation placed on a class or interface.
+ * A {@link StereotypesProvider} that extracts a stereotype for each
+ * {@code javax.*} annotation <i>present</i> on a class or interface.
 *
 * @author Stephane Nicoll
 * @since 5.0
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2021 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
@@ -22,7 +22,7 @@ import javax.lang.model.element.Element;

 /**
 * Provide the list of stereotypes that match an {@link Element}.
- * If an element has one more stereotypes, it is referenced in the index
+ * <p>If an element has one or more stereotypes, it is referenced in the index
 * of candidate components and each stereotype can be queried individually.
 *
 * @author Stephane Nicoll
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2021 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
@@ -138,7 +138,7 @@ abstract class AbstractJCacheOperation<A extends Annotation> implements JCacheOp

 	@Override
 	public String toString() {
-		return getOperationDescription().append("]").toString();
+		return getOperationDescription().append(']').toString();
 	}

 	/**
@@ -148,7 +148,7 @@ abstract class AbstractJCacheOperation<A extends Annotation> implements JCacheOp
 	protected StringBuilder getOperationDescription() {
 		StringBuilder result = new StringBuilder();
 		result.append(getClass().getSimpleName());
-		result.append("[");
+		result.append('[');
 		result.append(this.methodDetails);
 		return result;
 	}
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2021 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
@@ -71,9 +71,9 @@ public class CacheEvictOperation extends CacheOperation {
 		@Override
 		protected StringBuilder getOperationDescription() {
 			StringBuilder sb = super.getOperationDescription();
-			sb.append(",");
+			sb.append(',');
 			sb.append(this.cacheWide);
-			sb.append(",");
+			sb.append(',');
 			sb.append(this.beforeInvocation);
 			return sb;
 		}
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2021 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
@@ -216,13 +216,13 @@ public abstract class CacheOperation implements BasicOperation {
 		 */
 		protected StringBuilder getOperationDescription() {
 			StringBuilder result = new StringBuilder(getClass().getSimpleName());
-			result.append("[").append(this.name);
+			result.append('[').append(this.name);
 			result.append("] caches=").append(this.cacheNames);
 			result.append(" | key='").append(this.key);
 			result.append("' | keyGenerator='").append(this.keyGenerator);
 			result.append("' | cacheManager='").append(this.cacheManager);
 			result.append("' | cacheResolver='").append(this.cacheResolver);
-			result.append("' | condition='").append(this.condition).append("'");
+			result.append("' | condition='").append(this.condition).append('\'');
 			return result;
 		}

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2021 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
@@ -66,7 +66,7 @@ public class CachePutOperation extends CacheOperation {
 			StringBuilder sb = super.getOperationDescription();
 			sb.append(" | unless='");
 			sb.append(this.unless);
-			sb.append("'");
+			sb.append('\'');
 			return sb;
 		}

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2021 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
@@ -79,10 +79,10 @@ public class CacheableOperation extends CacheOperation {
 			StringBuilder sb = super.getOperationDescription();
 			sb.append(" | unless='");
 			sb.append(this.unless);
-			sb.append("'");
+			sb.append('\'');
 			sb.append(" | sync='");
 			sb.append(this.sync);
-			sb.append("'");
+			sb.append('\'');
 			return sb;
 		}

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2021 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
@@ -16,6 +16,7 @@

 package org.springframework.context;

+import java.time.Clock;
 import java.util.EventObject;

 /**
@@ -37,18 +38,37 @@ public abstract class ApplicationEvent extends EventObject {


 	/**
-	 * Create a new {@code ApplicationEvent}.
+	 * Create a new {@code ApplicationEvent} with its {@link #getTimestamp() timestamp}
+	 * set to {@link System#currentTimeMillis()}.
 	 * @param source the object on which the event initially occurred or with
 	 * which the event is associated (never {@code null})
+	 * @see #ApplicationEvent(Object, Clock)
 	 */
 	public ApplicationEvent(Object source) {
 		super(source);
 		this.timestamp = System.currentTimeMillis();
 	}

+	/**
+	 * Create a new {@code ApplicationEvent} with its {@link #getTimestamp() timestamp}
+	 * set to the value returned by {@link Clock#millis()} in the provided {@link Clock}.
+	 * <p>This constructor is typically used in testing scenarios.
+	 * @param source the object on which the event initially occurred or with
+	 * which the event is associated (never {@code null})
+	 * @param clock a clock which will provide the timestamp
+	 * @since 5.3.8
+	 * @see #ApplicationEvent(Object)
+	 */
+	public ApplicationEvent(Object source, Clock clock) {
+		super(source);
+		this.timestamp = clock.millis();
+	}
+

 	/**
-	 * Return the system time in milliseconds when the event occurred.
+	 * Return the time in milliseconds when the event occurred.
+	 * @see #ApplicationEvent(Object)
+	 * @see #ApplicationEvent(Object, Clock)
 	 */
 	public final long getTimestamp() {
 		return this.timestamp;
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2021 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
@@ -19,13 +19,15 @@ package org.springframework.context.annotation;
 import org.springframework.beans.factory.parsing.Problem;
 import org.springframework.beans.factory.parsing.ProblemReporter;
 import org.springframework.core.type.MethodMetadata;
+import org.springframework.lang.Nullable;

 /**
- * Represents a {@link Configuration @Configuration} class method marked with the
- * {@link Bean @Bean} annotation.
+ * Represents a {@link Configuration @Configuration} class method annotated with
+ * {@link Bean @Bean}.
 *
 * @author Chris Beams
 * @author Juergen Hoeller
+ * @author Sam Brannen
 * @since 3.0
 * @see ConfigurationClass
 * @see ConfigurationClassParser
@@ -33,7 +35,7 @@ import org.springframework.core.type.MethodMetadata;
 */
 final class BeanMethod extends ConfigurationMethod {

-	public BeanMethod(MethodMetadata metadata, ConfigurationClass configurationClass) {
+	BeanMethod(MethodMetadata metadata, ConfigurationClass configurationClass) {
 		super(metadata, configurationClass);
 	}

@@ -52,12 +54,28 @@ final class BeanMethod extends ConfigurationMethod {
 		}
 	}

+	@Override
+	public boolean equals(@Nullable Object obj) {
+		return ((this == obj) || ((obj instanceof BeanMethod) &&
+				this.metadata.equals(((BeanMethod) obj).metadata)));
+	}
+
+	@Override
+	public int hashCode() {
+		return this.metadata.hashCode();
+	}
+
+	@Override
+	public String toString() {
+		return "BeanMethod: " + this.metadata;
+	}

 	private class NonOverridableMethodError extends Problem {

-		public NonOverridableMethodError() {
+		NonOverridableMethodError() {
 			super(String.format("@Bean method '%s' must not be private or final; change the method's modifiers to continue",
 					getMetadata().getMethodName()), getResourceLocation());
 		}
 	}
+
 }
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2021 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
@@ -36,7 +36,7 @@ import org.springframework.util.ClassUtils;

 /**
 * Represents a user-defined {@link Configuration @Configuration} class.
- * Includes a set of {@link Bean} methods, including all such methods
+ * <p>Includes a set of {@link Bean} methods, including all such methods
 * defined in the ancestry of the class, in a 'flattened-out' manner.
 *
 * @author Chris Beams
@@ -74,7 +74,7 @@ final class ConfigurationClass {
 	 * @param beanName must not be {@code null}
 	 * @see ConfigurationClass#ConfigurationClass(Class, ConfigurationClass)
 	 */
-	public ConfigurationClass(MetadataReader metadataReader, String beanName) {
+	ConfigurationClass(MetadataReader metadataReader, String beanName) {
 		Assert.notNull(beanName, "Bean name must not be null");
 		this.metadata = metadataReader.getAnnotationMetadata();
 		this.resource = metadataReader.getResource();
@@ -89,7 +89,7 @@ final class ConfigurationClass {
 	 * @param importedBy the configuration class importing this one or {@code null}
 	 * @since 3.1.1
 	 */
-	public ConfigurationClass(MetadataReader metadataReader, @Nullable ConfigurationClass importedBy) {
+	ConfigurationClass(MetadataReader metadataReader, @Nullable ConfigurationClass importedBy) {
 		this.metadata = metadataReader.getAnnotationMetadata();
 		this.resource = metadataReader.getResource();
 		this.importedBy.add(importedBy);
@@ -101,7 +101,7 @@ final class ConfigurationClass {
 	 * @param beanName name of the {@code @Configuration} class bean
 	 * @see ConfigurationClass#ConfigurationClass(Class, ConfigurationClass)
 	 */
-	public ConfigurationClass(Class<?> clazz, String beanName) {
+	ConfigurationClass(Class<?> clazz, String beanName) {
 		Assert.notNull(beanName, "Bean name must not be null");
 		this.metadata = AnnotationMetadata.introspect(clazz);
 		this.resource = new DescriptiveResource(clazz.getName());
@@ -116,7 +116,7 @@ final class ConfigurationClass {
 	 * @param importedBy the configuration class importing this one (or {@code null})
 	 * @since 3.1.1
 	 */
-	public ConfigurationClass(Class<?> clazz, @Nullable ConfigurationClass importedBy) {
+	ConfigurationClass(Class<?> clazz, @Nullable ConfigurationClass importedBy) {
 		this.metadata = AnnotationMetadata.introspect(clazz);
 		this.resource = new DescriptiveResource(clazz.getName());
 		this.importedBy.add(importedBy);
@@ -128,7 +128,7 @@ final class ConfigurationClass {
 	 * @param beanName name of the {@code @Configuration} class bean
 	 * @see ConfigurationClass#ConfigurationClass(Class, ConfigurationClass)
 	 */
-	public ConfigurationClass(AnnotationMetadata metadata, String beanName) {
+	ConfigurationClass(AnnotationMetadata metadata, String beanName) {
 		Assert.notNull(beanName, "Bean name must not be null");
 		this.metadata = metadata;
 		this.resource = new DescriptiveResource(metadata.getClassName());
@@ -136,19 +136,19 @@ final class ConfigurationClass {
 	}


-	public AnnotationMetadata getMetadata() {
+	AnnotationMetadata getMetadata() {
 		return this.metadata;
 	}

-	public Resource getResource() {
+	Resource getResource() {
 		return this.resource;
 	}

-	public String getSimpleName() {
+	String getSimpleName() {
 		return ClassUtils.getShortName(getMetadata().getClassName());
 	}

-	public void setBeanName(String beanName) {
+	void setBeanName(String beanName) {
 		this.beanName = beanName;
 	}

@@ -171,7 +171,7 @@ final class ConfigurationClass {
 	 * Merge the imported-by declarations from the given configuration class into this one.
 	 * @since 4.0.5
 	 */
-	public void mergeImportedBy(ConfigurationClass otherConfigClass) {
+	void mergeImportedBy(ConfigurationClass otherConfigClass) {
 		this.importedBy.addAll(otherConfigClass.importedBy);
 	}

@@ -181,35 +181,35 @@ final class ConfigurationClass {
 	 * @since 4.0.5
 	 * @see #isImported()
 	 */
-	public Set<ConfigurationClass> getImportedBy() {
+	Set<ConfigurationClass> getImportedBy() {
 		return this.importedBy;
 	}

-	public void addBeanMethod(BeanMethod method) {
+	void addBeanMethod(BeanMethod method) {
 		this.beanMethods.add(method);
 	}

-	public Set<BeanMethod> getBeanMethods() {
+	Set<BeanMethod> getBeanMethods() {
 		return this.beanMethods;
 	}

-	public void addImportedResource(String importedResource, Class<? extends BeanDefinitionReader> readerClass) {
+	void addImportedResource(String importedResource, Class<? extends BeanDefinitionReader> readerClass) {
 		this.importedResources.put(importedResource, readerClass);
 	}

-	public void addImportBeanDefinitionRegistrar(ImportBeanDefinitionRegistrar registrar, AnnotationMetadata importingClassMetadata) {
+	void addImportBeanDefinitionRegistrar(ImportBeanDefinitionRegistrar registrar, AnnotationMetadata importingClassMetadata) {
 		this.importBeanDefinitionRegistrars.put(registrar, importingClassMetadata);
 	}

-	public Map<ImportBeanDefinitionRegistrar, AnnotationMetadata> getImportBeanDefinitionRegistrars() {
+	Map<ImportBeanDefinitionRegistrar, AnnotationMetadata> getImportBeanDefinitionRegistrars() {
 		return this.importBeanDefinitionRegistrars;
 	}

-	public Map<String, Class<? extends BeanDefinitionReader>> getImportedResources() {
+	Map<String, Class<? extends BeanDefinitionReader>> getImportedResources() {
 		return this.importedResources;
 	}

-	public void validate(ProblemReporter problemReporter) {
+	void validate(ProblemReporter problemReporter) {
 		// A configuration class may not be final (CGLIB limitation) unless it declares proxyBeanMethods=false
 		Map<String, Object> attributes = this.metadata.getAnnotationAttributes(Configuration.class.getName());
 		if (attributes != null && (Boolean) attributes.get("proxyBeanMethods")) {
@@ -244,7 +244,7 @@ final class ConfigurationClass {
 	 */
 	private class FinalConfigurationProblem extends Problem {

-		public FinalConfigurationProblem() {
+		FinalConfigurationProblem() {
 			super(String.format("@Configuration class '%s' may not be final. Remove the final modifier to continue.",
 					getSimpleName()), new Location(getResource(), getMetadata()));
 		}
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2021 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
@@ -51,18 +51,9 @@ abstract class ConfigurationMethod {
 		return new Location(this.configurationClass.getResource(), this.metadata);
 	}

-	String getFullyQualifiedMethodName() {
-		return this.metadata.getDeclaringClassName() + "#" + this.metadata.getMethodName();
+	void validate(ProblemReporter problemReporter) {
 	}

-	static String getShortMethodName(String fullyQualifiedMethodName) {
-		return fullyQualifiedMethodName.substring(fullyQualifiedMethodName.indexOf('#') + 1);
-	}
-
-	public void validate(ProblemReporter problemReporter) {
-	}
-
-
 	@Override
 	public String toString() {
 		return String.format("[%s:name=%s,declaringClass=%s]",
@@ -396,7 +396,7 @@ public class ApplicationListenerMethodAdapter implements GenericApplicationListe
 	 * @param message error message to append the HandlerMethod details to
 	 */
 	protected String getDetailedErrorMessage(Object bean, String message) {
-		StringBuilder sb = new StringBuilder(message).append("\n");
+		StringBuilder sb = new StringBuilder(message).append('\n');
 		sb.append("HandlerMethod details: \n");
 		sb.append("Bean [").append(bean.getClass().getName()).append("]\n");
 		sb.append("Method [").append(this.method.toGenericString()).append("]\n");
@@ -426,7 +426,7 @@ public class ApplicationListenerMethodAdapter implements GenericApplicationListe
 		StringBuilder sb = new StringBuilder(getDetailedErrorMessage(bean, message));
 		sb.append("Resolved arguments: \n");
 		for (int i = 0; i < resolvedArgs.length; i++) {
-			sb.append("[").append(i).append("] ");
+			sb.append('[').append(i).append("] ");
 			if (resolvedArgs[i] == null) {
 				sb.append("[null] \n");
 			}
@@ -84,6 +84,7 @@ import org.springframework.core.annotation.AliasFor;
 * @author Sam Brannen
 * @since 4.2
 * @see EventListenerMethodProcessor
+ * @see org.springframework.transaction.event.TransactionalEventListener
 */
@Target({ElementType.METHOD, ElementType.ANNOTATION_TYPE})
@Retention(RetentionPolicy.RUNTIME)
@@ -133,7 +134,7 @@ public @interface EventListener {
 	 * An optional identifier for the listener, defaulting to the fully-qualified
 	 * signature of the declaring method (e.g. "mypackage.MyClass.myMethod()").
 	 * @since 5.3.5
-	 * @see org.springframework.context.ApplicationListener#getListenerId()
+	 * @see SmartApplicationListener#getListenerId()
 	 * @see ApplicationEventMulticaster#removeApplicationListeners(Predicate)
 	 */
 	String id() default "";
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2020 the original author or authors.
+ * Copyright 2002-2021 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
@@ -205,12 +205,12 @@ public class LiveBeansView implements LiveBeansViewMBean, ApplicationContextAwar
 				}
 			}
 			result.append("]\n");
-			result.append("}");
+			result.append('}');
 			if (it.hasNext()) {
 				result.append(",\n");
 			}
 		}
-		result.append("]");
+		result.append(']');
 		return result.toString();
 	}

@@ -112,10 +112,10 @@ public class ThreadPoolTaskExecutor extends ExecutorConfigurationSupport
 	 */
 	public void setCorePoolSize(int corePoolSize) {
 		synchronized (this.poolSizeMonitor) {
-			this.corePoolSize = corePoolSize;
 			if (this.threadPoolExecutor != null) {
 				this.threadPoolExecutor.setCorePoolSize(corePoolSize);
 			}
+			this.corePoolSize = corePoolSize;
 		}
 	}

@@ -135,10 +135,10 @@ public class ThreadPoolTaskExecutor extends ExecutorConfigurationSupport
 	 */
 	public void setMaxPoolSize(int maxPoolSize) {
 		synchronized (this.poolSizeMonitor) {
-			this.maxPoolSize = maxPoolSize;
 			if (this.threadPoolExecutor != null) {
 				this.threadPoolExecutor.setMaximumPoolSize(maxPoolSize);
 			}
+			this.maxPoolSize = maxPoolSize;
 		}
 	}

@@ -158,10 +158,10 @@ public class ThreadPoolTaskExecutor extends ExecutorConfigurationSupport
 	 */
 	public void setKeepAliveSeconds(int keepAliveSeconds) {
 		synchronized (this.poolSizeMonitor) {
-			this.keepAliveSeconds = keepAliveSeconds;
 			if (this.threadPoolExecutor != null) {
 				this.threadPoolExecutor.setKeepAliveTime(keepAliveSeconds, TimeUnit.SECONDS);
 			}
+			this.keepAliveSeconds = keepAliveSeconds;
 		}
 	}

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2020 the original author or authors.
+ * Copyright 2002-2021 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
@@ -53,6 +53,8 @@ import org.springframework.util.concurrent.ListenableFutureTask;
 * @since 3.0
 * @see #setPoolSize
 * @see #setRemoveOnCancelPolicy
+ * @see #setContinueExistingPeriodicTasksAfterShutdownPolicy
+ * @see #setExecuteExistingDelayedTasksAfterShutdownPolicy
 * @see #setThreadFactory
 * @see #setErrorHandler
 */
@@ -64,6 +66,10 @@ public class ThreadPoolTaskScheduler extends ExecutorConfigurationSupport

 	private volatile boolean removeOnCancelPolicy;

+	private volatile boolean continueExistingPeriodicTasksAfterShutdownPolicy;
+
+	private volatile boolean executeExistingDelayedTasksAfterShutdownPolicy = true;
+
 	@Nullable
 	private volatile ErrorHandler errorHandler;

@@ -84,26 +90,54 @@ public class ThreadPoolTaskScheduler extends ExecutorConfigurationSupport
 	 */
 	public void setPoolSize(int poolSize) {
 		Assert.isTrue(poolSize > 0, "'poolSize' must be 1 or higher");
-		this.poolSize = poolSize;
 		if (this.scheduledExecutor instanceof ScheduledThreadPoolExecutor) {
 			((ScheduledThreadPoolExecutor) this.scheduledExecutor).setCorePoolSize(poolSize);
 		}
+		this.poolSize = poolSize;
 	}

 	/**
 	 * Set the remove-on-cancel mode on {@link ScheduledThreadPoolExecutor}.
 	 * <p>Default is {@code false}. If set to {@code true}, the target executor will be
-	 * switched into remove-on-cancel mode (if possible, with a soft fallback otherwise).
+	 * switched into remove-on-cancel mode (if possible).
 	 * <p><b>This setting can be modified at runtime, for example through JMX.</b>
+	 * @see ScheduledThreadPoolExecutor#setRemoveOnCancelPolicy
 	 */
-	public void setRemoveOnCancelPolicy(boolean removeOnCancelPolicy) {
-		this.removeOnCancelPolicy = removeOnCancelPolicy;
+	public void setRemoveOnCancelPolicy(boolean flag) {
 		if (this.scheduledExecutor instanceof ScheduledThreadPoolExecutor) {
-			((ScheduledThreadPoolExecutor) this.scheduledExecutor).setRemoveOnCancelPolicy(removeOnCancelPolicy);
+			((ScheduledThreadPoolExecutor) this.scheduledExecutor).setRemoveOnCancelPolicy(flag);
 		}
-		else if (removeOnCancelPolicy && this.scheduledExecutor != null) {
-			logger.debug("Could not apply remove-on-cancel policy - not a ScheduledThreadPoolExecutor");
+		this.removeOnCancelPolicy = flag;
+	}
+
+	/**
+	 * Set whether to continue existing periodic tasks even when this executor has been shutdown.
+	 * <p>Default is {@code false}. If set to {@code true}, the target executor will be
+	 * switched into continuing periodic tasks (if possible).
+	 * <p><b>This setting can be modified at runtime, for example through JMX.</b>
+	 * @since 5.3.9
+	 * @see ScheduledThreadPoolExecutor#setContinueExistingPeriodicTasksAfterShutdownPolicy
+	 */
+	public void setContinueExistingPeriodicTasksAfterShutdownPolicy(boolean flag) {
+		if (this.scheduledExecutor instanceof ScheduledThreadPoolExecutor) {
+			((ScheduledThreadPoolExecutor) this.scheduledExecutor).setContinueExistingPeriodicTasksAfterShutdownPolicy(flag);
 		}
+		this.continueExistingPeriodicTasksAfterShutdownPolicy = flag;
+	}
+
+	/**
+	 * Set whether to execute existing delayed tasks even when this executor has been shutdown.
+	 * <p>Default is {@code true}. If set to {@code false}, the target executor will be
+	 * switched into dropping remaining tasks (if possible).
+	 * <p><b>This setting can be modified at runtime, for example through JMX.</b>
+	 * @since 5.3.9
+	 * @see ScheduledThreadPoolExecutor#setExecuteExistingDelayedTasksAfterShutdownPolicy
+	 */
+	public void setExecuteExistingDelayedTasksAfterShutdownPolicy(boolean flag) {
+		if (this.scheduledExecutor instanceof ScheduledThreadPoolExecutor) {
+			((ScheduledThreadPoolExecutor) this.scheduledExecutor).setExecuteExistingDelayedTasksAfterShutdownPolicy(flag);
+		}
+		this.executeExistingDelayedTasksAfterShutdownPolicy = flag;
 	}

 	/**
@@ -135,12 +169,16 @@ public class ThreadPoolTaskScheduler extends ExecutorConfigurationSupport

 		this.scheduledExecutor = createExecutor(this.poolSize, threadFactory, rejectedExecutionHandler);

-		if (this.removeOnCancelPolicy) {
-			if (this.scheduledExecutor instanceof ScheduledThreadPoolExecutor) {
-				((ScheduledThreadPoolExecutor) this.scheduledExecutor).setRemoveOnCancelPolicy(true);
+		if (this.scheduledExecutor instanceof ScheduledThreadPoolExecutor) {
+			ScheduledThreadPoolExecutor scheduledPoolExecutor = (ScheduledThreadPoolExecutor) this.scheduledExecutor;
+			if (this.removeOnCancelPolicy) {
+				scheduledPoolExecutor.setRemoveOnCancelPolicy(true);
 			}
-			else {
-				logger.debug("Could not apply remove-on-cancel policy - not a ScheduledThreadPoolExecutor");
+			if (this.continueExistingPeriodicTasksAfterShutdownPolicy) {
+				scheduledPoolExecutor.setContinueExistingPeriodicTasksAfterShutdownPolicy(true);
+			}
+			if (!this.executeExistingDelayedTasksAfterShutdownPolicy) {
+				scheduledPoolExecutor.setExecuteExistingDelayedTasksAfterShutdownPolicy(false);
 			}
 		}

@@ -201,18 +239,6 @@ public class ThreadPoolTaskScheduler extends ExecutorConfigurationSupport
 		return getScheduledThreadPoolExecutor().getPoolSize();
 	}

-	/**
-	 * Return the current setting for the remove-on-cancel mode.
-	 * <p>Requires an underlying {@link ScheduledThreadPoolExecutor}.
-	 */
-	public boolean isRemoveOnCancelPolicy() {
-		if (this.scheduledExecutor == null) {
-			// Not initialized yet: return our setting for the time being.
-			return this.removeOnCancelPolicy;
-		}
-		return getScheduledThreadPoolExecutor().getRemoveOnCancelPolicy();
-	}
-
 	/**
 	 * Return the number of currently active threads.
 	 * <p>Requires an underlying {@link ScheduledThreadPoolExecutor}.
@@ -227,6 +253,21 @@ public class ThreadPoolTaskScheduler extends ExecutorConfigurationSupport
 		return getScheduledThreadPoolExecutor().getActiveCount();
 	}

+	/**
+	 * Return the current setting for the remove-on-cancel mode.
+	 * <p>Requires an underlying {@link ScheduledThreadPoolExecutor}.
+	 * @deprecated as of 5.3.9, in favor of direct
+	 * {@link #getScheduledThreadPoolExecutor()} access
+	 */
+	@Deprecated
+	public boolean isRemoveOnCancelPolicy() {
+		if (this.scheduledExecutor == null) {
+			// Not initialized yet: return our setting for the time being.
+			return this.removeOnCancelPolicy;
+		}
+		return getScheduledThreadPoolExecutor().getRemoveOnCancelPolicy();
+	}
+

 	// SchedulingTaskExecutor implementation

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2020 the original author or authors.
+ * Copyright 2002-2021 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
@@ -192,6 +192,11 @@ final class BitsCronField extends CronField {
 			while (current != next && count++ < CronExpression.MAX_ATTEMPTS) {
 				temporal = type().elapseUntil(temporal, next);
 				current = type().get(temporal);
+				next = nextSetBit(current);
+				if (next == -1) {
+					temporal = type().rollForward(temporal);
+					next = nextSetBit(0);
+				}
 			}
 			if (count >= CronExpression.MAX_ATTEMPTS) {
 				return null;
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2020 the original author or authors.
+ * Copyright 2002-2021 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
@@ -66,8 +66,9 @@ public final class CronExpression {
 			CronField daysOfWeek,
 			String expression) {

+		// reverse order, to make big changes first
 		// to make sure we end up at 0 nanos, we add an extra field
-		this.fields = new CronField[]{CronField.zeroNanos(), seconds, minutes, hours, daysOfMonth, months, daysOfWeek};
+		this.fields = new CronField[]{daysOfWeek, months, daysOfMonth, hours, minutes, seconds, CronField.zeroNanos()};
 		this.expression = expression;
 	}

@@ -202,6 +203,25 @@ public final class CronExpression {
 		}
 	}

+	/**
+	 * Determine whether the given string represents a valid cron expression.
+	 * @param expression the expression to evaluate
+	 * @return {@code true} if the given expression is a valid cron expression
+	 * @since 5.3.8
+	 */
+	public static boolean isValidExpression(@Nullable String expression) {
+		if (expression == null) {
+			return false;
+		}
+		try {
+			parse(expression);
+			return true;
+		}
+		catch (IllegalArgumentException ex) {
+			return false;
+		}
+	}
+

 	private static String resolveMacros(String expression) {
 		expression = expression.trim();
@@ -230,9 +230,7 @@ abstract class CronField {
 		 * Elapse the given temporal for the difference between the current
 		 * value of this field and the goal value. Typically, the returned
 		 * temporal will have the given goal as the current value for this type,
-		 * but this is not the case for {@link #DAY_OF_MONTH}. For instance,
-		 * if {@code goal} is 31, and {@code temporal} is April 16th,
-		 * this method returns May 1st, because April 31st does not exist.
+		 * but this is not the case for {@link #DAY_OF_MONTH}.
 		 * @param temporal the temporal to elapse
 		 * @param goal the goal value
 		 * @param <T> the type of temporal
@@ -247,8 +245,9 @@ abstract class CronField {
 					return cast(temporal.with(this.field, goal));
 				}
 				else {
-					// goal is invalid, eg. 29th Feb, lets try to get as close as possible
-					return this.field.getBaseUnit().addTo(temporal, goal - current);
+					// goal is invalid, eg. 29th Feb, so roll forward
+					long amount = range.getMaximum() - current + 1;
+					return this.field.getBaseUnit().addTo(temporal, amount);
 				}
 			}
 			else {
@@ -334,6 +334,9 @@ final class QuartzCronField extends CronField {
 				// We ended up before the start, roll forward and try again
 				temporal = this.rollForwardType.rollForward(temporal);
 				result = adjust(temporal);
+				if (result != null) {
+					result = type().reset(result);
+				}
 			}
 		}
 		return result;
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2021 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
@@ -18,6 +18,7 @@ package org.springframework.validation.support;

 import java.util.Map;

+import org.springframework.lang.Nullable;
 import org.springframework.ui.ConcurrentModel;
 import org.springframework.validation.BindingResult;

@@ -36,17 +37,19 @@ import org.springframework.validation.BindingResult;
 * @author Rossen Stoyanchev
 * @since 5.0
 * @see BindingResult
+ * @see BindingAwareModelMap
 */
@SuppressWarnings("serial")
 public class BindingAwareConcurrentModel extends ConcurrentModel {

 	@Override
-	public Object put(String key, Object value) {
+	@Nullable
+	public Object put(String key, @Nullable Object value) {
 		removeBindingResultIfNecessary(key, value);
 		return super.put(key, value);
 	}

-	private void removeBindingResultIfNecessary(String key, Object value) {
+	private void removeBindingResultIfNecessary(String key, @Nullable Object value) {
 		if (!key.startsWith(BindingResult.MODEL_KEY_PREFIX)) {
 			String resultKey = BindingResult.MODEL_KEY_PREFIX + key;
 			BindingResult result = (BindingResult) get(resultKey);
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2017 the original author or authors.
+ * Copyright 2002-2021 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
@@ -18,6 +18,7 @@ package org.springframework.validation.support;

 import java.util.Map;

+import org.springframework.lang.Nullable;
 import org.springframework.ui.ExtendedModelMap;
 import org.springframework.validation.BindingResult;

@@ -39,7 +40,7 @@ import org.springframework.validation.BindingResult;
 public class BindingAwareModelMap extends ExtendedModelMap {

 	@Override
-	public Object put(String key, Object value) {
+	public Object put(String key, @Nullable Object value) {
 		removeBindingResultIfNecessary(key, value);
 		return super.put(key, value);
 	}
@@ -50,7 +51,7 @@ public class BindingAwareModelMap extends ExtendedModelMap {
 		super.putAll(map);
 	}

-	private void removeBindingResultIfNecessary(Object key, Object value) {
+	private void removeBindingResultIfNecessary(Object key, @Nullable Object value) {
 		if (key instanceof String) {
 			String attributeName = (String) key;
 			if (!attributeName.startsWith(BindingResult.MODEL_KEY_PREFIX)) {
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2021 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
@@ -1110,7 +1110,7 @@ open class BeanDefinitionDsl internal constructor (private val init: BeanDefinit
 		}

 		/**
-		 * Return an provider for the specified bean, allowing for lazy on-demand retrieval
+		 * Return a provider for the specified bean, allowing for lazy on-demand retrieval
 		 * of instances, including availability and uniqueness options.
 		 * @see org.springframework.beans.factory.BeanFactory.getBeanProvider
 		 */
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2021 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
@@ -28,6 +28,7 @@ import org.junit.jupiter.api.Test;
 import org.springframework.aop.TargetSource;
 import org.springframework.aop.framework.ProxyFactory;
 import org.springframework.aop.support.AopUtils;
+import org.springframework.aop.support.DefaultIntroductionAdvisor;
 import org.springframework.aop.target.SingletonTargetSource;
 import org.springframework.beans.MutablePropertyValues;
 import org.springframework.beans.factory.BeanFactory;
@@ -219,7 +220,7 @@ public class AutoProxyCreatorTests {

 		MutablePropertyValues pvs = new MutablePropertyValues();
 		pvs.add("proxyFactoryBean", "false");
-		sac.registerSingleton("testAutoProxyCreator", TestAutoProxyCreator.class, pvs);
+		sac.registerSingleton("testAutoProxyCreator", IntroductionTestAutoProxyCreator.class, pvs);

 		sac.registerSingleton("noInterfaces", NoInterfaces.class);
 		sac.registerSingleton("containerCallbackInterfacesOnly", ContainerCallbackInterfacesOnly.class);
@@ -248,9 +249,9 @@ public class AutoProxyCreatorTests {
 		singletonNoInterceptor.getName();
 		assertThat(tapc.testInterceptor.nrOfInvocations).isEqualTo(0);
 		singletonToBeProxied.getAge();
-		assertThat(tapc.testInterceptor.nrOfInvocations).isEqualTo(1);
-		prototypeToBeProxied.getSpouse();
 		assertThat(tapc.testInterceptor.nrOfInvocations).isEqualTo(2);
+		prototypeToBeProxied.getSpouse();
+		assertThat(tapc.testInterceptor.nrOfInvocations).isEqualTo(4);
 	}

 	@Test
@@ -404,7 +405,7 @@ public class AutoProxyCreatorTests {
 			else if (name.endsWith("ToBeProxied")) {
 				boolean isFactoryBean = FactoryBean.class.isAssignableFrom(beanClass);
 				if ((this.proxyFactoryBean && isFactoryBean) || (this.proxyObject && !isFactoryBean)) {
-					return new Object[] {this.testInterceptor};
+					return getAdvicesAndAdvisors();
 				}
 				else {
 					return DO_NOT_PROXY;
@@ -414,6 +415,10 @@ public class AutoProxyCreatorTests {
 				return PROXY_WITHOUT_ADDITIONAL_INTERCEPTORS;
 			}
 		}
+
+		protected Object[] getAdvicesAndAdvisors() {
+			return new Object[] {this.testInterceptor};
+		}
 	}


@@ -426,6 +431,17 @@ public class AutoProxyCreatorTests {
 	}


+	@SuppressWarnings("serial")
+	public static class IntroductionTestAutoProxyCreator extends TestAutoProxyCreator {
+
+		protected Object[] getAdvicesAndAdvisors() {
+			DefaultIntroductionAdvisor advisor = new DefaultIntroductionAdvisor(this.testInterceptor);
+			advisor.addInterface(Serializable.class);
+			return new Object[] {this.testInterceptor, advisor};
+		}
+	}
+
+
 	/**
 	 * Interceptor that counts the number of non-finalize method calls.
 	 */
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2021 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
@@ -47,8 +47,9 @@ import static org.springframework.util.ClassUtils.convertClassNameToResourcePath
 public class QualifierAnnotationTests {

 	private static final String CLASSNAME = QualifierAnnotationTests.class.getName();
+
 	private static final String CONFIG_LOCATION =
-		format("classpath:%s-context.xml", convertClassNameToResourcePath(CLASSNAME));
+			format("classpath:%s-context.xml", convertClassNameToResourcePath(CLASSNAME));


 	@Test
@@ -146,7 +146,7 @@ class XmlBeanFactoryTests {
 		assertThat(emmasJenks != georgiasJenks).as("Emma and georgia think they have a different boyfriend").isTrue();
 		assertThat(emmasJenks.getName().equals("Andrew")).as("Emmas jenks has right name").isTrue();
 		assertThat(emmasJenks != xbf.getBean("jenks")).as("Emmas doesn't equal new ref").isTrue();
-		assertThat(emmasJenks.getName().equals("Andrew")).as("Georgias jenks has right name").isTrue();
+		assertThat(georgiasJenks.getName().equals("Andrew")).as("Georgias jenks has right name").isTrue();
 		assertThat(emmasJenks.equals(georgiasJenks)).as("They are object equal").isTrue();
 		assertThat(emmasJenks.equals(xbf.getBean("jenks"))).as("They object equal direct ref").isTrue();
 	}
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2021 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
@@ -29,7 +29,7 @@ import static org.assertj.core.api.Assertions.assertThat;

 /**
 * Tests regarding overloading and overriding of bean methods.
- * Related to SPR-6618.
+ * <p>Related to SPR-6618.
 *
 * @author Chris Beams
 * @author Phillip Webb
@@ -41,7 +41,7 @@ public class BeanMethodPolymorphismTests {
 	@Test
 	public void beanMethodDetectedOnSuperClass() {
 		AnnotationConfigApplicationContext ctx = new AnnotationConfigApplicationContext(Config.class);
-		ctx.getBean("testBean", TestBean.class);
+		assertThat(ctx.getBean("testBean", TestBean.class)).isNotNull();
 	}

 	@Test
@@ -0,0 +1,202 @@
+/*
+ * Copyright 2002-2021 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.context.annotation;
+
+import java.util.Comparator;
+import java.util.List;
+import java.util.stream.Collectors;
+
+import org.junit.jupiter.api.Test;
+
+import org.springframework.beans.factory.parsing.FailFastProblemReporter;
+import org.springframework.beans.factory.support.DefaultListableBeanFactory;
+import org.springframework.core.env.StandardEnvironment;
+import org.springframework.core.io.DefaultResourceLoader;
+import org.springframework.core.type.classreading.CachingMetadataReaderFactory;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * Integration tests for {@link ConfigurationClassParser}, {@link ConfigurationClass},
+ * and {@link BeanMethod}.
+ *
+ * @author Sam Brannen
+ * @since 5.3.9
+ */
+class ConfigurationClassAndBeanMethodTests {
+
+	@Test
+	void verifyEquals() throws Exception {
+		ConfigurationClass configurationClass1 = newConfigurationClass(Config1.class);
+		ConfigurationClass configurationClass2 = newConfigurationClass(Config1.class);
+		ConfigurationClass configurationClass3 = newConfigurationClass(Config2.class);
+
+		assertThat(configurationClass1.equals(null)).isFalse();
+		assertThat(configurationClass1).isNotSameAs(configurationClass2);
+
+		assertThat(configurationClass1.equals(configurationClass1)).isTrue();
+		assertThat(configurationClass2.equals(configurationClass2)).isTrue();
+		assertThat(configurationClass1.equals(configurationClass2)).isTrue();
+		assertThat(configurationClass2.equals(configurationClass1)).isTrue();
+
+		assertThat(configurationClass1.equals(configurationClass3)).isFalse();
+		assertThat(configurationClass3.equals(configurationClass2)).isFalse();
+
+		// ---------------------------------------------------------------------
+
+		List<BeanMethod> beanMethods1 = getBeanMethods(configurationClass1);
+		BeanMethod beanMethod_1_0 = beanMethods1.get(0);
+		BeanMethod beanMethod_1_1 = beanMethods1.get(1);
+		BeanMethod beanMethod_1_2 = beanMethods1.get(2);
+
+		List<BeanMethod> beanMethods2 = getBeanMethods(configurationClass2);
+		BeanMethod beanMethod_2_0 = beanMethods2.get(0);
+		BeanMethod beanMethod_2_1 = beanMethods2.get(1);
+		BeanMethod beanMethod_2_2 = beanMethods2.get(2);
+
+		List<BeanMethod> beanMethods3 = getBeanMethods(configurationClass3);
+		BeanMethod beanMethod_3_0 = beanMethods3.get(0);
+		BeanMethod beanMethod_3_1 = beanMethods3.get(1);
+		BeanMethod beanMethod_3_2 = beanMethods3.get(2);
+
+		assertThat(beanMethod_1_0.equals(null)).isFalse();
+		assertThat(beanMethod_1_0).isNotSameAs(beanMethod_2_0);
+
+		assertThat(beanMethod_1_0.equals(beanMethod_1_0)).isTrue();
+		assertThat(beanMethod_1_0.equals(beanMethod_2_0)).isTrue();
+		assertThat(beanMethod_1_1.equals(beanMethod_2_1)).isTrue();
+		assertThat(beanMethod_1_2.equals(beanMethod_2_2)).isTrue();
+
+		assertThat(beanMethod_1_0.getMetadata().getMethodName()).isEqualTo(beanMethod_3_0.getMetadata().getMethodName());
+		assertThat(beanMethod_1_0.equals(beanMethod_3_0)).isFalse();
+		assertThat(beanMethod_1_1.equals(beanMethod_3_1)).isFalse();
+		assertThat(beanMethod_1_2.equals(beanMethod_3_2)).isFalse();
+	}
+
+	@Test
+	void verifyHashCode() throws Exception {
+		ConfigurationClass configurationClass1 = newConfigurationClass(Config1.class);
+		ConfigurationClass configurationClass2 = newConfigurationClass(Config1.class);
+		ConfigurationClass configurationClass3 = newConfigurationClass(Config2.class);
+
+		assertThat(configurationClass1).hasSameHashCodeAs(configurationClass2);
+		assertThat(configurationClass1).doesNotHaveSameHashCodeAs(configurationClass3);
+
+		// ---------------------------------------------------------------------
+
+		List<BeanMethod> beanMethods1 = getBeanMethods(configurationClass1);
+		BeanMethod beanMethod_1_0 = beanMethods1.get(0);
+		BeanMethod beanMethod_1_1 = beanMethods1.get(1);
+		BeanMethod beanMethod_1_2 = beanMethods1.get(2);
+
+		List<BeanMethod> beanMethods2 = getBeanMethods(configurationClass2);
+		BeanMethod beanMethod_2_0 = beanMethods2.get(0);
+		BeanMethod beanMethod_2_1 = beanMethods2.get(1);
+		BeanMethod beanMethod_2_2 = beanMethods2.get(2);
+
+		List<BeanMethod> beanMethods3 = getBeanMethods(configurationClass3);
+		BeanMethod beanMethod_3_0 = beanMethods3.get(0);
+		BeanMethod beanMethod_3_1 = beanMethods3.get(1);
+		BeanMethod beanMethod_3_2 = beanMethods3.get(2);
+
+		assertThat(beanMethod_1_0).hasSameHashCodeAs(beanMethod_2_0);
+		assertThat(beanMethod_1_1).hasSameHashCodeAs(beanMethod_2_1);
+		assertThat(beanMethod_1_2).hasSameHashCodeAs(beanMethod_2_2);
+
+		assertThat(beanMethod_1_0).doesNotHaveSameHashCodeAs(beanMethod_3_0);
+		assertThat(beanMethod_1_1).doesNotHaveSameHashCodeAs(beanMethod_3_1);
+		assertThat(beanMethod_1_2).doesNotHaveSameHashCodeAs(beanMethod_3_2);
+	}
+
+	@Test
+	void verifyToString() throws Exception {
+		ConfigurationClass configurationClass = newConfigurationClass(Config1.class);
+		assertThat(configurationClass.toString())
+			.startsWith("ConfigurationClass: beanName 'Config1', class path resource");
+
+		List<BeanMethod> beanMethods = getBeanMethods(configurationClass);
+		String prefix = "BeanMethod: " + Config1.class.getName();
+		assertThat(beanMethods.get(0).toString()).isEqualTo(prefix + ".bean0()");
+		assertThat(beanMethods.get(1).toString()).isEqualTo(prefix + ".bean1(java.lang.String)");
+		assertThat(beanMethods.get(2).toString()).isEqualTo(prefix + ".bean2(java.lang.String,java.lang.Integer)");
+	}
+
+
+	private static ConfigurationClass newConfigurationClass(Class<?> clazz) throws Exception {
+		ConfigurationClassParser parser = newParser();
+		parser.parse(clazz.getName(), clazz.getSimpleName());
+		assertThat(parser.getConfigurationClasses()).hasSize(1);
+		return parser.getConfigurationClasses().iterator().next();
+	}
+
+	private static ConfigurationClassParser newParser() {
+		return new ConfigurationClassParser(
+				new CachingMetadataReaderFactory(),
+				new FailFastProblemReporter(),
+				new StandardEnvironment(),
+				new DefaultResourceLoader(),
+				new AnnotationBeanNameGenerator(),
+				new DefaultListableBeanFactory());
+	}
+
+	private static List<BeanMethod> getBeanMethods(ConfigurationClass configurationClass) {
+		List<BeanMethod> beanMethods = configurationClass.getBeanMethods().stream()
+				.sorted(Comparator.comparing(beanMethod -> beanMethod.getMetadata().getMethodName()))
+				.collect(Collectors.toList());
+		assertThat(beanMethods).hasSize(3);
+		return beanMethods;
+	}
+
+	static class Config1 {
+
+		@Bean
+		String bean0() {
+			return "";
+		}
+
+		@Bean
+		String bean1(String text) {
+			return "";
+		}
+
+		@Bean
+		String bean2(String text, Integer num) {
+			return "";
+		}
+
+	}
+
+	static class Config2 {
+
+		@Bean
+		String bean0() {
+			return "";
+		}
+
+		@Bean
+		String bean1(String text) {
+			return "";
+		}
+
+		@Bean
+		String bean2(String text, Integer num) {
+			return "";
+		}
+
+	}
+
+}
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2020 the original author or authors.
+ * Copyright 2002-2021 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
@@ -16,21 +16,100 @@

 package org.springframework.scheduling.concurrent;

+import java.util.concurrent.TimeUnit;
+
+import org.junit.jupiter.api.Test;
+
 import org.springframework.core.task.AsyncListenableTaskExecutor;

+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+
 /**
 * @author Juergen Hoeller
 * @since 5.0.5
 */
 class ThreadPoolTaskExecutorTests extends AbstractSchedulingTaskExecutorTests {

+	private final ThreadPoolTaskExecutor executor = new ThreadPoolTaskExecutor();
+
+
 	@Override
 	protected AsyncListenableTaskExecutor buildExecutor() {
-		ThreadPoolTaskExecutor executor = new ThreadPoolTaskExecutor();
 		executor.setThreadNamePrefix(this.threadNamePrefix);
 		executor.setMaxPoolSize(1);
 		executor.afterPropertiesSet();
 		return executor;
 	}

+
+	@Test
+	void modifyCorePoolSizeWhileRunning() {
+		assertThat(executor.getCorePoolSize()).isEqualTo(1);
+		assertThat(executor.getThreadPoolExecutor().getCorePoolSize()).isEqualTo(1);
+
+		executor.setCorePoolSize(0);
+
+		assertThat(executor.getCorePoolSize()).isEqualTo(0);
+		assertThat(executor.getThreadPoolExecutor().getCorePoolSize()).isEqualTo(0);
+	}
+
+	@Test
+	void modifyCorePoolSizeWithInvalidValueWhileRunning() {
+		assertThat(executor.getCorePoolSize()).isEqualTo(1);
+		assertThat(executor.getThreadPoolExecutor().getCorePoolSize()).isEqualTo(1);
+
+		assertThatThrownBy(() -> executor.setCorePoolSize(-1))
+				.isInstanceOf(IllegalArgumentException.class);
+
+		assertThat(executor.getCorePoolSize()).isEqualTo(1);
+		assertThat(executor.getThreadPoolExecutor().getCorePoolSize()).isEqualTo(1);
+	}
+
+	@Test
+	void modifyMaxPoolSizeWhileRunning() {
+		assertThat(executor.getMaxPoolSize()).isEqualTo(1);
+		assertThat(executor.getThreadPoolExecutor().getMaximumPoolSize()).isEqualTo(1);
+
+		executor.setMaxPoolSize(5);
+
+		assertThat(executor.getMaxPoolSize()).isEqualTo(5);
+		assertThat(executor.getThreadPoolExecutor().getMaximumPoolSize()).isEqualTo(5);
+	}
+
+	@Test
+	void modifyMaxPoolSizeWithInvalidValueWhileRunning() {
+		assertThat(executor.getMaxPoolSize()).isEqualTo(1);
+		assertThat(executor.getThreadPoolExecutor().getMaximumPoolSize()).isEqualTo(1);
+
+		assertThatThrownBy(() -> executor.setMaxPoolSize(0))
+				.isInstanceOf(IllegalArgumentException.class);
+
+		assertThat(executor.getMaxPoolSize()).isEqualTo(1);
+		assertThat(executor.getThreadPoolExecutor().getMaximumPoolSize()).isEqualTo(1);
+	}
+
+	@Test
+	void modifyKeepAliveSecondsWhileRunning() {
+		assertThat(executor.getKeepAliveSeconds()).isEqualTo(60);
+		assertThat(executor.getThreadPoolExecutor().getKeepAliveTime(TimeUnit.SECONDS)).isEqualTo(60);
+
+		executor.setKeepAliveSeconds(10);
+
+		assertThat(executor.getKeepAliveSeconds()).isEqualTo(10);
+		assertThat(executor.getThreadPoolExecutor().getKeepAliveTime(TimeUnit.SECONDS)).isEqualTo(10);
+	}
+
+	@Test
+	void modifyKeepAliveSecondsWithInvalidValueWhileRunning() {
+		assertThat(executor.getKeepAliveSeconds()).isEqualTo(60);
+		assertThat(executor.getThreadPoolExecutor().getKeepAliveTime(TimeUnit.SECONDS)).isEqualTo(60);
+
+		assertThatThrownBy(() -> executor.setKeepAliveSeconds(-10))
+				.isInstanceOf(IllegalArgumentException.class);
+
+		assertThat(executor.getKeepAliveSeconds()).isEqualTo(60);
+		assertThat(executor.getThreadPoolExecutor().getKeepAliveTime(TimeUnit.SECONDS)).isEqualTo(60);
+	}
+
 }
@@ -51,6 +51,16 @@ class CronExpressionTests {
 		}
 	};

+	@Test
+	public void isValidExpression() {
+		assertThat(CronExpression.isValidExpression(null)).isFalse();
+		assertThat(CronExpression.isValidExpression("")).isFalse();
+		assertThat(CronExpression.isValidExpression("*")).isFalse();
+		assertThat(CronExpression.isValidExpression("* * * * *")).isFalse();
+		assertThat(CronExpression.isValidExpression("* * * * * * *")).isFalse();
+
+		assertThat(CronExpression.isValidExpression("* * * * * *")).isTrue();
+	}

 	@Test
 	void matchAll() {
@@ -497,6 +507,29 @@ class CronExpressionTests {
 		assertThat(actual.getDayOfMonth()).isEqualTo(13);
 	}

+	@Test
+	public void everyTenDays() {
+		CronExpression cronExpression = CronExpression.parse("0 15 12 */10 1-8 5");
+
+		LocalDateTime last = LocalDateTime.parse("2021-04-30T12:14:59");
+		LocalDateTime expected = LocalDateTime.parse("2021-05-21T12:15");
+		LocalDateTime actual = cronExpression.next(last);
+		assertThat(actual).isNotNull();
+		assertThat(actual).isEqualTo(expected);
+
+		last = actual;
+		expected = LocalDateTime.parse("2021-06-11T12:15");
+		actual = cronExpression.next(last);
+		assertThat(actual).isNotNull();
+		assertThat(actual).isEqualTo(expected);
+
+		last = actual;
+		expected = LocalDateTime.parse("2022-01-21T12:15");
+		actual = cronExpression.next(last);
+		assertThat(actual).isNotNull();
+		assertThat(actual).isEqualTo(expected);
+	}
+
 	@Test
 	void yearly() {
 		CronExpression expression = CronExpression.parse("@yearly");
@@ -1286,6 +1319,21 @@ class CronExpressionTests {
 		assertThat(actual).isEqualTo(expected);
 	}

+	@Test
+	public void various() {
+		CronExpression cronExpression = CronExpression.parse("3-57 13-28 17,18 1,15 3-12 6#1");
+		LocalDateTime last =     LocalDateTime.of(2022, 9, 15, 17, 44, 11);
+		LocalDateTime expected = LocalDateTime.of(2022, 10, 1, 17, 13, 3);
+		LocalDateTime actual = cronExpression.next(last);
+		assertThat(actual).isNotNull();
+		assertThat(actual).isEqualTo(expected);

+		cronExpression = CronExpression.parse("*/28 56 22 */6 * *");
+		last = LocalDateTime.of(2022, 2, 27, 8, 0, 42);
+		expected = LocalDateTime.of(2022, 3, 1, 22, 56, 0);
+		actual = cronExpression.next(last);
+		assertThat(actual).isNotNull();
+		assertThat(actual).isEqualTo(expected);
+	}

 }
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2020 the original author or authors.
+ * Copyright 2002-2021 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
@@ -17,10 +17,7 @@
@file:JvmName("CoroutinesUtils")
 package org.springframework.core

-import kotlinx.coroutines.Deferred
-import kotlinx.coroutines.Dispatchers
-import kotlinx.coroutines.GlobalScope
-import kotlinx.coroutines.async
+import kotlinx.coroutines.*
 import kotlinx.coroutines.flow.Flow
 import kotlinx.coroutines.reactive.awaitSingleOrNull
 import kotlinx.coroutines.reactor.asFlux
@@ -48,6 +45,8 @@ internal fun <T: Any> deferredToMono(source: Deferred<T>) =
 * @author Sebastien Deleuze
 * @since 5.2
 */
+@Suppress("DEPRECATION")
+@OptIn(DelicateCoroutinesApi::class)
 internal fun <T: Any> monoToDeferred(source: Mono<T>) =
 		GlobalScope.async(Dispatchers.Unconfined) { source.awaitSingleOrNull() }

@@ -88,6 +88,9 @@ public class ClassReader {
   */
  static final int EXPAND_ASM_INSNS = 256;

+  /** The maximum size of array to allocate. */
+  private static final int MAX_BUFFER_SIZE = 1024 * 1024;
+
  /** The size of the temporary byte array used to read class input streams chunk by chunk. */
  private static final int INPUT_STREAM_DATA_CHUNK_SIZE = 4096;

@@ -191,7 +194,7 @@ public class ClassReader {
    this.b = classFileBuffer;
    // Check the class' major_version. This field is after the magic and minor_version fields, which
    // use 4 and 2 bytes respectively.
-    if (checkClassVersion && readShort(classFileOffset + 6) > Opcodes.V17) {
+    if (checkClassVersion && readShort(classFileOffset + 6) > Opcodes.V18) {
      throw new IllegalArgumentException(
          "Unsupported class file major version " + readShort(classFileOffset + 6));
    }
@@ -310,13 +313,19 @@ public class ClassReader {
    if (inputStream == null) {
      throw new IOException("Class not found");
    }
+    int bufferSize = calculateBufferSize(inputStream);
    try (ByteArrayOutputStream outputStream = new ByteArrayOutputStream()) {
-      byte[] data = new byte[INPUT_STREAM_DATA_CHUNK_SIZE];
+      byte[] data = new byte[bufferSize];
      int bytesRead;
-      while ((bytesRead = inputStream.read(data, 0, data.length)) != -1) {
+      int readCount = 0;
+      while ((bytesRead = inputStream.read(data, 0, bufferSize)) != -1) {
        outputStream.write(data, 0, bytesRead);
+        readCount++;
      }
      outputStream.flush();
+      if (readCount == 1) {
+        return data;
+      }
      return outputStream.toByteArray();
    } finally {
      if (close) {
@@ -325,6 +334,20 @@ public class ClassReader {
    }
  }

+  private static int calculateBufferSize(final InputStream inputStream) throws IOException {
+    int expectedLength = inputStream.available();
+    /*
+     * Some implementations can return 0 while holding available data
+     * (e.g. new FileInputStream("/proc/a_file"))
+     * Also in some pathological cases a very small number might be returned,
+     * and in this case we use default size
+     */
+    if (expectedLength < 256) {
+      return INPUT_STREAM_DATA_CHUNK_SIZE;
+    }
+    return Math.min(expectedLength, MAX_BUFFER_SIZE);
+  }
+
  // -----------------------------------------------------------------------------------------------
  // Accessors
  // -----------------------------------------------------------------------------------------------
@@ -3456,7 +3479,6 @@ public class ClassReader {
  private int[] readBootstrapMethodsAttribute(final int maxStringLength) {
    char[] charBuffer = new char[maxStringLength];
    int currentAttributeOffset = getFirstAttributeOffset();
-    int[] currentBootstrapMethodOffsets = null;
    for (int i = readUnsignedShort(currentAttributeOffset - 2); i > 0; --i) {
      // Read the attribute_info's attribute_name and attribute_length fields.
      String attributeName = readUTF8(currentAttributeOffset, charBuffer);
@@ -3464,17 +3486,17 @@ public class ClassReader {
      currentAttributeOffset += 6;
      if (Constants.BOOTSTRAP_METHODS.equals(attributeName)) {
        // Read the num_bootstrap_methods field and create an array of this size.
-        currentBootstrapMethodOffsets = new int[readUnsignedShort(currentAttributeOffset)];
+        int[] result = new int[readUnsignedShort(currentAttributeOffset)];
        // Compute and store the offset of each 'bootstrap_methods' array field entry.
        int currentBootstrapMethodOffset = currentAttributeOffset + 2;
-        for (int j = 0; j < currentBootstrapMethodOffsets.length; ++j) {
-          currentBootstrapMethodOffsets[j] = currentBootstrapMethodOffset;
+        for (int j = 0; j < result.length; ++j) {
+          result[j] = currentBootstrapMethodOffset;
          // Skip the bootstrap_method_ref and num_bootstrap_arguments fields (2 bytes each),
          // as well as the bootstrap_arguments array field (of size num_bootstrap_arguments * 2).
          currentBootstrapMethodOffset +=
              4 + readUnsignedShort(currentBootstrapMethodOffset + 2) * 2;
        }
-        return currentBootstrapMethodOffsets;
+        return result;
      }
      currentAttributeOffset += attributeLength;
    }
@@ -30,8 +30,8 @@ package org.springframework.asm;
 /**
 * A visitor to visit a Java class. The methods of this class must be called in the following order:
 * {@code visit} [ {@code visitSource} ] [ {@code visitModule} ][ {@code visitNestHost} ][ {@code
- * visitPermittedSubclass} ][ {@code visitOuterClass} ] ( {@code visitAnnotation} | {@code
- * visitTypeAnnotation} | {@code visitAttribute} )* ( {@code visitNestMember} | {@code
+ * visitOuterClass} ] ( {@code visitAnnotation} | {@code visitTypeAnnotation} | {@code
+ * visitAttribute} )* ( {@code visitNestMember} | [ {@code * visitPermittedSubclass} ] | {@code
 * visitInnerClass} | {@code visitRecordComponent} | {@code visitField} | {@code visitMethod} )*
 * {@code visitEnd}.
 *
@@ -79,7 +79,7 @@ public class ClassWriter extends ClassVisitor {

  /**
   * The access_flags field of the JVMS ClassFile structure. This field can contain ASM specific
-   * access flags, such as {@link Opcodes#ACC_DEPRECATED} or {}@link Opcodes#ACC_RECORD}, which are
+   * access flags, such as {@link Opcodes#ACC_DEPRECATED} or {@link Opcodes#ACC_RECORD}, which are
   * removed when generating the ClassFile structure.
   */
  private int accessFlags;
@@ -282,6 +282,7 @@ public interface Opcodes {
  int V15 = 0 << 16 | 59;
  int V16 = 0 << 16 | 60;
  int V17 = 0 << 16 | 61;
+  int V18 = 0 << 16 | 62;

  /**
   * Version flag indicating that the class is using 'preview' features.
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2021 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
@@ -324,7 +324,7 @@ public class Constants {
 		for (int i = 0; i < propertyName.length(); i++) {
 			char c = propertyName.charAt(i);
 			if (Character.isUpperCase(c)) {
-				parsedPrefix.append("_");
+				parsedPrefix.append('_');
 				parsedPrefix.append(c);
 			}
 			else {
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2021 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
@@ -394,9 +394,11 @@ public class AnnotationAttributes extends LinkedHashMap<String, Object> {
 			sb.append(entry.getKey());
 			sb.append('=');
 			sb.append(valueToString(entry.getValue()));
-			sb.append(entries.hasNext() ? ", " : "");
+			if (entries.hasNext()) {
+				sb.append(", ");
+			}
 		}
-		sb.append("}");
+		sb.append('}');
 		return sb.toString();
 	}

@@ -177,17 +177,17 @@ final class SynthesizedMergedAnnotationInvocationHandler<A extends Annotation> i
 	private String annotationToString() {
 		String string = this.string;
 		if (string == null) {
-			StringBuilder builder = new StringBuilder("@").append(this.type.getName()).append("(");
+			StringBuilder builder = new StringBuilder("@").append(this.type.getName()).append('(');
 			for (int i = 0; i < this.attributes.size(); i++) {
 				Method attribute = this.attributes.get(i);
 				if (i > 0) {
 					builder.append(", ");
 				}
 				builder.append(attribute.getName());
-				builder.append("=");
+				builder.append('=');
 				builder.append(toString(getAttributeValue(attribute)));
 			}
-			builder.append(")");
+			builder.append(')');
 			string = builder.toString();
 			this.string = string;
 		}
@@ -206,7 +206,7 @@ final class SynthesizedMergedAnnotationInvocationHandler<A extends Annotation> i
 				}
 				builder.append(toString(Array.get(value, i)));
 			}
-			builder.append("]");
+			builder.append(']');
 			return builder.toString();
 		}
 		return String.valueOf(value);
@@ -513,7 +513,7 @@ public class TypeDescriptor implements Serializable {
 	public String toString() {
 		StringBuilder builder = new StringBuilder();
 		for (Annotation ann : getAnnotations()) {
-			builder.append("@").append(ann.annotationType().getName()).append(' ');
+			builder.append('@').append(ann.annotationType().getName()).append(' ');
 		}
 		builder.append(getResolvableType());
 		return builder.toString();
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2020 the original author or authors.
+ * Copyright 2002-2021 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
@@ -71,7 +71,7 @@ public abstract class DataBufferUtils {
 	//---------------------------------------------------------------------

 	/**
-	 * Obtain a {@link InputStream} from the given supplier, and read it into a
+	 * Obtain an {@link InputStream} from the given supplier, and read it into a
 	 * {@code Flux} of {@code DataBuffer}s. Closes the input stream when the
 	 * Flux is terminated.
 	 * @param inputStreamSupplier the supplier for the input stream to read from
@@ -125,7 +125,7 @@ public abstract class DataBufferUtils {
 	}

 	/**
-	 * Obtain a {@code AsynchronousFileChannel} from the given supplier, and
+	 * Obtain an {@code AsynchronousFileChannel} from the given supplier, and
 	 * read it into a {@code Flux} of {@code DataBuffer}s, starting at the given
 	 * position. Closes the channel when the Flux is terminated.
 	 * @param channelSupplier the supplier for the channel to read from
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2020 the original author or authors.
+ * Copyright 2002-2021 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
@@ -29,16 +29,16 @@ import java.util.function.Supplier;
 */
 class DefaultApplicationStartup implements ApplicationStartup {

+	private static final DefaultStartupStep DEFAULT_STARTUP_STEP = new DefaultStartupStep();
+
 	@Override
 	public DefaultStartupStep start(String name) {
-		return new DefaultStartupStep();
+		return DEFAULT_STARTUP_STEP;
 	}


 	static class DefaultStartupStep implements StartupStep {

-		boolean recorded = false;
-
 		private final DefaultTags TAGS = new DefaultTags();

 		@Override
@@ -63,23 +63,17 @@ class DefaultApplicationStartup implements ApplicationStartup {

 		@Override
 		public StartupStep tag(String key, String value) {
-			if (this.recorded) {
-				throw new IllegalArgumentException();
-			}
 			return this;
 		}

 		@Override
 		public StartupStep tag(String key, Supplier<String> value) {
-			if (this.recorded) {
-				throw new IllegalArgumentException();
-			}
 			return this;
 		}

 		@Override
 		public void end() {
-			this.recorded = true;
+
 		}


@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2020 the original author or authors.
+ * Copyright 2002-2021 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
@@ -16,8 +16,9 @@

 package org.springframework.core.metrics.jfr;

-import java.util.ArrayDeque;
 import java.util.Deque;
+import java.util.concurrent.ConcurrentLinkedDeque;
+import java.util.concurrent.atomic.AtomicLong;

 import org.springframework.core.metrics.ApplicationStartup;
 import org.springframework.core.metrics.StartupStep;
@@ -37,24 +38,23 @@ import org.springframework.core.metrics.StartupStep;
 */
 public class FlightRecorderApplicationStartup implements ApplicationStartup {

-	private long currentSequenceId;
+	private final AtomicLong currentSequenceId = new AtomicLong(0);

 	private final Deque<Long> currentSteps;


 	public FlightRecorderApplicationStartup() {
-		this.currentSequenceId = 0;
-		this.currentSteps = new ArrayDeque<>();
-		this.currentSteps.offerFirst(0L);
+		this.currentSteps = new ConcurrentLinkedDeque<>();
+		this.currentSteps.offerFirst(this.currentSequenceId.get());
 	}


 	@Override
 	public StartupStep start(String name) {
-		FlightRecorderStartupStep step = new FlightRecorderStartupStep(++this.currentSequenceId, name,
-				this.currentSteps.getFirst(), committedStep -> this.currentSteps.removeFirst());
-		this.currentSteps.offerFirst(this.currentSequenceId);
-		return step;
+		long sequenceId = this.currentSequenceId.incrementAndGet();
+		this.currentSteps.offerFirst(sequenceId);
+		return new FlightRecorderStartupStep(sequenceId, name,
+				this.currentSteps.getFirst(), committedStep -> this.currentSteps.removeFirstOccurrence(sequenceId));
 	}

 }
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2015 the original author or authors.
+ * Copyright 2002-2021 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
@@ -18,7 +18,7 @@ package org.springframework.core.type;

 /**
 * Interface that defines abstract access to the annotations of a specific
- * class, in a form that does not require that class to be loaded yet.
+ * method, in a form that does not require that method's class to be loaded yet.
 *
 * @author Juergen Hoeller
 * @author Mark Pollack
@@ -32,42 +32,42 @@ package org.springframework.core.type;
 public interface MethodMetadata extends AnnotatedTypeMetadata {

 	/**
-	 * Return the name of the method.
+	 * Get the name of the underlying method.
 	 */
 	String getMethodName();

 	/**
-	 * Return the fully-qualified name of the class that declares this method.
+	 * Get the fully-qualified name of the class that declares the underlying method.
 	 */
 	String getDeclaringClassName();

 	/**
-	 * Return the fully-qualified name of this method's declared return type.
+	 * Get the fully-qualified name of the underlying method's declared return type.
 	 * @since 4.2
 	 */
 	String getReturnTypeName();

 	/**
-	 * Return whether the underlying method is effectively abstract:
-	 * i.e. marked as abstract on a class or declared as a regular,
+	 * Determine whether the underlying method is effectively abstract:
+	 * i.e. marked as abstract in a class or declared as a regular,
 	 * non-default method in an interface.
 	 * @since 4.2
 	 */
 	boolean isAbstract();

 	/**
-	 * Return whether the underlying method is declared as 'static'.
+	 * Determine whether the underlying method is declared as 'static'.
 	 */
 	boolean isStatic();

 	/**
-	 * Return whether the underlying method is marked as 'final'.
+	 * Determine whether the underlying method is marked as 'final'.
 	 */
 	boolean isFinal();

 	/**
-	 * Return whether the underlying method is overridable,
-	 * i.e. not marked as static, final or private.
+	 * Determine whether the underlying method is overridable,
+	 * i.e. not marked as static, final, or private.
 	 */
 	boolean isOverridable();

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2020 the original author or authors.
+ * Copyright 2002-2021 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
@@ -165,12 +165,12 @@ public class StandardAnnotationMetadata extends StandardClassMetadata implements
 		return annotatedMethods != null ? annotatedMethods : Collections.emptySet();
 	}

-	private boolean isAnnotatedMethod(Method method, String annotationName) {
+
+	private static boolean isAnnotatedMethod(Method method, String annotationName) {
 		return !method.isBridge() && method.getAnnotations().length > 0 &&
 				AnnotatedElementUtils.isAnnotated(method, annotationName);
 	}

-
 	static AnnotationMetadata from(Class<?> introspectedClass) {
 		return new StandardAnnotationMetadata(introspectedClass, true);
 	}
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2021 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
@@ -28,6 +28,7 @@ import org.springframework.util.StringUtils;
 * to introspect a given {@code Class}.
 *
 * @author Juergen Hoeller
+ * @author Sam Brannen
 * @since 2.5
 */
 public class StandardClassMetadata implements ClassMetadata {
@@ -119,4 +120,20 @@ public class StandardClassMetadata implements ClassMetadata {
 		return StringUtils.toStringArray(memberClassNames);
 	}

+	@Override
+	public boolean equals(@Nullable Object obj) {
+		return ((this == obj) || ((obj instanceof StandardClassMetadata) &&
+				getIntrospectedClass().equals(((StandardClassMetadata) obj).getIntrospectedClass())));
+	}
+
+	@Override
+	public int hashCode() {
+		return getIntrospectedClass().hashCode();
+	}
+
+	@Override
+	public String toString() {
+		return getClassName();
+	}
+
 }
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2021 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
@@ -36,6 +36,7 @@ import org.springframework.util.MultiValueMap;
 * @author Mark Pollack
 * @author Chris Beams
 * @author Phillip Webb
+ * @author Sam Brannen
 * @since 3.0
 */
 public class StandardMethodMetadata implements MethodMetadata {
@@ -150,4 +151,20 @@ public class StandardMethodMetadata implements MethodMetadata {
 				annotationName, classValuesAsString, false);
 	}

+	@Override
+	public boolean equals(@Nullable Object obj) {
+		return ((this == obj) || ((obj instanceof StandardMethodMetadata) &&
+				this.introspectedMethod.equals(((StandardMethodMetadata) obj).introspectedMethod)));
+	}
+
+	@Override
+	public int hashCode() {
+		return this.introspectedMethod.hashCode();
+	}
+
+	@Override
+	public String toString() {
+		return this.introspectedMethod.toString();
+	}
+
 }
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2021 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
@@ -23,7 +23,6 @@ import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.function.Consumer;
-import java.util.function.Supplier;

 import org.springframework.asm.AnnotationVisitor;
 import org.springframework.asm.SpringAsmInfo;
@@ -121,7 +120,7 @@ class MergedAnnotationReadingVisitor<A extends Annotation> extends AnnotationVis
 	@SuppressWarnings("unchecked")
 	@Nullable
 	static <A extends Annotation> AnnotationVisitor get(@Nullable ClassLoader classLoader,
-			@Nullable Supplier<Object> sourceSupplier, String descriptor, boolean visible,
+			@Nullable Object source, String descriptor, boolean visible,
 			Consumer<MergedAnnotation<A>> consumer) {

 		if (!visible) {
@@ -133,7 +132,6 @@ class MergedAnnotationReadingVisitor<A extends Annotation> extends AnnotationVis
 			return null;
 		}

-		Object source = (sourceSupplier != null ? sourceSupplier.get() : null);
 		try {
 			Class<A> annotationType = (Class<A>) ClassUtils.forName(typeName, classLoader);
 			return new MergedAnnotationReadingVisitor<>(classLoader, source, annotationType, consumer);
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2020 the original author or authors.
+ * Copyright 2002-2021 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
@@ -31,6 +31,7 @@ import org.springframework.lang.Nullable;
 * {@link SimpleAnnotationMetadataReadingVisitor}.
 *
 * @author Phillip Webb
+ * @author Sam Brannen
 * @since 5.2
 */
 final class SimpleAnnotationMetadata implements AnnotationMetadata {
@@ -156,4 +157,20 @@ final class SimpleAnnotationMetadata implements AnnotationMetadata {
 		return this.annotations;
 	}

+	@Override
+	public boolean equals(@Nullable Object obj) {
+		return ((this == obj) || ((obj instanceof SimpleAnnotationMetadata) &&
+				this.className.equals(((SimpleAnnotationMetadata) obj).className)));
+	}
+
+	@Override
+	public int hashCode() {
+		return this.className.hashCode();
+	}
+
+	@Override
+	public String toString() {
+		return this.className;
+	}
+
 }
@@ -117,7 +117,7 @@ final class SimpleAnnotationMetadataReadingVisitor extends ClassVisitor {
 	@Override
 	@Nullable
 	public AnnotationVisitor visitAnnotation(String descriptor, boolean visible) {
-		return MergedAnnotationReadingVisitor.get(this.classLoader, this::getSource,
+		return MergedAnnotationReadingVisitor.get(this.classLoader, getSource(),
 				descriptor, visible, this.annotations::add);
 	}

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2021 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
@@ -19,12 +19,13 @@ package org.springframework.core.type.classreading;
 import org.springframework.asm.Opcodes;
 import org.springframework.core.annotation.MergedAnnotations;
 import org.springframework.core.type.MethodMetadata;
+import org.springframework.lang.Nullable;

 /**
- * {@link MethodMetadata} created from a
- * {@link SimpleMethodMetadataReadingVisitor}.
+ * {@link MethodMetadata} created from a {@link SimpleMethodMetadataReadingVisitor}.
 *
 * @author Phillip Webb
+ * @author Sam Brannen
 * @since 5.2
 */
 final class SimpleMethodMetadata implements MethodMetadata {
@@ -37,16 +38,20 @@ final class SimpleMethodMetadata implements MethodMetadata {

 	private final String returnTypeName;

+	// The source implements equals(), hashCode(), and toString() for the underlying method.
+	private final Object source;
+
 	private final MergedAnnotations annotations;


-	public SimpleMethodMetadata(String methodName, int access, String declaringClassName,
-			String returnTypeName, MergedAnnotations annotations) {
+	SimpleMethodMetadata(String methodName, int access, String declaringClassName,
+			String returnTypeName, Object source, MergedAnnotations annotations) {

 		this.methodName = methodName;
 		this.access = access;
 		this.declaringClassName = declaringClassName;
 		this.returnTypeName = returnTypeName;
+		this.source = source;
 		this.annotations = annotations;
 	}

@@ -86,7 +91,7 @@ final class SimpleMethodMetadata implements MethodMetadata {
 		return !isStatic() && !isFinal() && !isPrivate();
 	}

-	public boolean isPrivate() {
+	private boolean isPrivate() {
 		return (this.access & Opcodes.ACC_PRIVATE) != 0;
 	}

@@ -95,4 +100,20 @@ final class SimpleMethodMetadata implements MethodMetadata {
 		return this.annotations;
 	}

+	@Override
+	public boolean equals(@Nullable Object obj) {
+		return ((this == obj) || ((obj instanceof SimpleMethodMetadata) &&
+				this.source.equals(((SimpleMethodMetadata) obj).source)));
+	}
+
+	@Override
+	public int hashCode() {
+		return this.source.hashCode();
+	}
+
+	@Override
+	public String toString() {
+		return this.source.toString();
+	}
+
 }
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2021 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
@@ -32,6 +32,7 @@ import org.springframework.lang.Nullable;
 * ASM method visitor that creates {@link SimpleMethodMetadata}.
 *
 * @author Phillip Webb
+ * @author Sam Brannen
 * @since 5.2
 */
 final class SimpleMethodMetadataReadingVisitor extends MethodVisitor {
@@ -43,7 +44,7 @@ final class SimpleMethodMetadataReadingVisitor extends MethodVisitor {

 	private final int access;

-	private final String name;
+	private final String methodName;

 	private final String descriptor;

@@ -56,13 +57,13 @@ final class SimpleMethodMetadataReadingVisitor extends MethodVisitor {


 	SimpleMethodMetadataReadingVisitor(@Nullable ClassLoader classLoader, String declaringClassName,
-			int access, String name, String descriptor, Consumer<SimpleMethodMetadata> consumer) {
+			int access, String methodName, String descriptor, Consumer<SimpleMethodMetadata> consumer) {

 		super(SpringAsmInfo.ASM_VERSION);
 		this.classLoader = classLoader;
 		this.declaringClassName = declaringClassName;
 		this.access = access;
-		this.name = name;
+		this.methodName = methodName;
 		this.descriptor = descriptor;
 		this.consumer = consumer;
 	}
@@ -71,7 +72,7 @@ final class SimpleMethodMetadataReadingVisitor extends MethodVisitor {
 	@Override
 	@Nullable
 	public AnnotationVisitor visitAnnotation(String descriptor, boolean visible) {
-		return MergedAnnotationReadingVisitor.get(this.classLoader, this::getSource,
+		return MergedAnnotationReadingVisitor.get(this.classLoader, getSource(),
 				descriptor, visible, this.annotations::add);
 	}

@@ -80,8 +81,8 @@ final class SimpleMethodMetadataReadingVisitor extends MethodVisitor {
 		if (!this.annotations.isEmpty()) {
 			String returnTypeName = Type.getReturnType(this.descriptor).getClassName();
 			MergedAnnotations annotations = MergedAnnotations.of(this.annotations);
-			SimpleMethodMetadata metadata = new SimpleMethodMetadata(this.name,
-					this.access, this.declaringClassName, returnTypeName, annotations);
+			SimpleMethodMetadata metadata = new SimpleMethodMetadata(this.methodName, this.access,
+					this.declaringClassName, returnTypeName, getSource(), annotations);
 			this.consumer.accept(metadata);
 		}
 	}
@@ -89,7 +90,7 @@ final class SimpleMethodMetadataReadingVisitor extends MethodVisitor {
 	private Object getSource() {
 		Source source = this.source;
 		if (source == null) {
-			source = new Source(this.declaringClassName, this.name, this.descriptor);
+			source = new Source(this.declaringClassName, this.methodName, this.descriptor);
 			this.source = source;
 		}
 		return source;
@@ -103,16 +104,16 @@ final class SimpleMethodMetadataReadingVisitor extends MethodVisitor {

 		private final String declaringClassName;

-		private final String name;
+		private final String methodName;

 		private final String descriptor;

 		@Nullable
 		private String toStringValue;

-		Source(String declaringClassName, String name, String descriptor) {
+		Source(String declaringClassName, String methodName, String descriptor) {
 			this.declaringClassName = declaringClassName;
-			this.name = name;
+			this.methodName = methodName;
 			this.descriptor = descriptor;
 		}

@@ -120,7 +121,7 @@ final class SimpleMethodMetadataReadingVisitor extends MethodVisitor {
 		public int hashCode() {
 			int result = 1;
 			result = 31 * result + this.declaringClassName.hashCode();
-			result = 31 * result + this.name.hashCode();
+			result = 31 * result + this.methodName.hashCode();
 			result = 31 * result + this.descriptor.hashCode();
 			return result;
 		}
@@ -135,7 +136,7 @@ final class SimpleMethodMetadataReadingVisitor extends MethodVisitor {
 			}
 			Source otherSource = (Source) other;
 			return (this.declaringClassName.equals(otherSource.declaringClassName) &&
-					this.name.equals(otherSource.name) && this.descriptor.equals(otherSource.descriptor));
+					this.methodName.equals(otherSource.methodName) && this.descriptor.equals(otherSource.descriptor));
 		}

 		@Override
@@ -144,14 +145,17 @@ final class SimpleMethodMetadataReadingVisitor extends MethodVisitor {
 			if (value == null) {
 				StringBuilder builder = new StringBuilder();
 				builder.append(this.declaringClassName);
-				builder.append(".");
-				builder.append(this.name);
+				builder.append('.');
+				builder.append(this.methodName);
 				Type[] argumentTypes = Type.getArgumentTypes(this.descriptor);
-				builder.append("(");
-				for (Type type : argumentTypes) {
-					builder.append(type.getClassName());
+				builder.append('(');
+				for (int i = 0; i < argumentTypes.length; i++) {
+					if (i != 0) {
+						builder.append(',');
+					}
+					builder.append(argumentTypes[i].getClassName());
 				}
-				builder.append(")");
+				builder.append(')');
 				value = builder.toString();
 				this.toStringValue = value;
 			}
@@ -88,13 +88,13 @@ public abstract class ClassUtils {
 	 * Map with primitive wrapper type as key and corresponding primitive
 	 * type as value, for example: Integer.class -> int.class.
 	 */
-	private static final Map<Class<?>, Class<?>> primitiveWrapperTypeMap = new IdentityHashMap<>(8);
+	private static final Map<Class<?>, Class<?>> primitiveWrapperTypeMap = new IdentityHashMap<>(9);

 	/**
 	 * Map with primitive type as key and corresponding wrapper
 	 * type as value, for example: int.class -> Integer.class.
 	 */
-	private static final Map<Class<?>, Class<?>> primitiveTypeToWrapperMap = new IdentityHashMap<>(8);
+	private static final Map<Class<?>, Class<?>> primitiveTypeToWrapperMap = new IdentityHashMap<>(9);

 	/**
 	 * Map with primitive type name as key and corresponding primitive
@@ -1322,7 +1322,7 @@ public abstract class ClassUtils {
 	 * Note that, despite being synthetic, bridge methods ({@link Method#isBridge()}) are considered
 	 * as user-level methods since they are eventually pointing to a user-declared generic method.
 	 * @param method the method to check
-	 * @return {@code true} if the method can be considered as user-declared; [@code false} otherwise
+	 * @return {@code true} if the method can be considered as user-declared; {@code false} otherwise
 	 */
 	public static boolean isUserLevelMethod(Method method) {
 		Assert.notNull(method, "Method must not be null");
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2020 the original author or authors.
+ * Copyright 2002-2021 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
@@ -302,7 +302,7 @@ public class StopWatch {
 			for (TaskInfo task : getTaskInfo()) {
 				sb.append(nf.format(task.getTimeNanos())).append("  ");
 				sb.append(pf.format((double) task.getTimeNanos() / getTotalTimeNanos())).append("  ");
-				sb.append(task.getTaskName()).append("\n");
+				sb.append(task.getTaskName()).append('\n');
 			}
 		}
 		return sb.toString();
@@ -320,7 +320,7 @@ public class StopWatch {
 			for (TaskInfo task : getTaskInfo()) {
 				sb.append("; [").append(task.getTaskName()).append("] took ").append(task.getTimeNanos()).append(" ns");
 				long percent = Math.round(100.0 * task.getTimeNanos() / getTotalTimeNanos());
-				sb.append(" = ").append(percent).append("%");
+				sb.append(" = ").append(percent).append('%');
 			}
 		}
 		else {
@@ -566,7 +566,7 @@ public abstract class StringUtils {

 		char[] chars = str.toCharArray();
 		chars[0] = updatedChar;
-		return new String(chars, 0, chars.length);
+		return new String(chars);
 	}

 	/**
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2020 the original author or authors.
+ * Copyright 2002-2021 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
@@ -21,13 +21,18 @@ import org.junit.jupiter.api.Test;
 import static org.assertj.core.api.Assertions.assertThat;

 /**
+ * Unit tests for {@link SimpleAliasRegistry}.
+ *
 * @author Juergen Hoeller
+ * @author Nha Vuong
+ * @author Sam Brannen
 */
 class SimpleAliasRegistryTests {

+	private final SimpleAliasRegistry registry = new SimpleAliasRegistry();
+
 	@Test
 	void aliasChaining() {
-		SimpleAliasRegistry registry = new SimpleAliasRegistry();
 		registry.registerAlias("test", "testAlias");
 		registry.registerAlias("testAlias", "testAlias2");
 		registry.registerAlias("testAlias2", "testAlias3");
@@ -42,7 +47,6 @@ class SimpleAliasRegistryTests {

 	@Test  // SPR-17191
 	void aliasChainingWithMultipleAliases() {
-		SimpleAliasRegistry registry = new SimpleAliasRegistry();
 		registry.registerAlias("name", "alias_a");
 		registry.registerAlias("name", "alias_b");
 		assertThat(registry.hasAlias("name", "alias_a")).isTrue();
@@ -60,4 +64,35 @@ class SimpleAliasRegistryTests {
 		assertThat(registry.hasAlias("real_name", "alias_c")).isTrue();
 	}

+	@Test
+	void removeAlias() {
+		registry.registerAlias("real_name", "nickname");
+		assertThat(registry.hasAlias("real_name", "nickname")).isTrue();
+
+		registry.removeAlias("nickname");
+		assertThat(registry.hasAlias("real_name", "nickname")).isFalse();
+	}
+
+	@Test
+	void isAlias() {
+		registry.registerAlias("real_name", "nickname");
+		assertThat(registry.isAlias("nickname")).isTrue();
+		assertThat(registry.isAlias("real_name")).isFalse();
+		assertThat(registry.isAlias("fake")).isFalse();
+	}
+
+	@Test
+	void getAliases() {
+		registry.registerAlias("test", "testAlias1");
+		assertThat(registry.getAliases("test")).containsExactly("testAlias1");
+
+		registry.registerAlias("testAlias1", "testAlias2");
+		registry.registerAlias("testAlias2", "testAlias3");
+		assertThat(registry.getAliases("test")).containsExactlyInAnyOrder("testAlias1", "testAlias2", "testAlias3");
+		assertThat(registry.getAliases("testAlias1")).containsExactlyInAnyOrder("testAlias2", "testAlias3");
+		assertThat(registry.getAliases("testAlias2")).containsExactly("testAlias3");
+
+		assertThat(registry.getAliases("testAlias3")).isEmpty();
+	}
+
 }
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2021 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
@@ -33,9 +33,51 @@ import static org.assertj.core.api.Assertions.entry;
 * Base class for {@link AnnotationMetadata} tests.
 *
 * @author Phillip Webb
+ * @author Sam Brannen
 */
 public abstract class AbstractAnnotationMetadataTests {

+	@Test
+	public void verifyEquals() throws Exception {
+		AnnotationMetadata testClass1 = get(TestClass.class);
+		AnnotationMetadata testClass2 = get(TestClass.class);
+		AnnotationMetadata testMemberClass1 = get(TestMemberClass.class);
+		AnnotationMetadata testMemberClass2 = get(TestMemberClass.class);
+
+		assertThat(testClass1.equals(null)).isFalse();
+
+		assertThat(testClass1.equals(testClass1)).isTrue();
+		assertThat(testClass2.equals(testClass2)).isTrue();
+		assertThat(testClass1.equals(testClass2)).isTrue();
+		assertThat(testClass2.equals(testClass1)).isTrue();
+
+		assertThat(testMemberClass1.equals(testMemberClass1)).isTrue();
+		assertThat(testMemberClass2.equals(testMemberClass2)).isTrue();
+		assertThat(testMemberClass1.equals(testMemberClass2)).isTrue();
+		assertThat(testMemberClass2.equals(testMemberClass1)).isTrue();
+
+		assertThat(testClass1.equals(testMemberClass1)).isFalse();
+		assertThat(testMemberClass1.equals(testClass1)).isFalse();
+	}
+
+	@Test
+	public void verifyHashCode() throws Exception {
+		AnnotationMetadata testClass1 = get(TestClass.class);
+		AnnotationMetadata testClass2 = get(TestClass.class);
+		AnnotationMetadata testMemberClass1 = get(TestMemberClass.class);
+		AnnotationMetadata testMemberClass2 = get(TestMemberClass.class);
+
+		assertThat(testClass1).hasSameHashCodeAs(testClass2);
+		assertThat(testMemberClass1).hasSameHashCodeAs(testMemberClass2);
+
+		assertThat(testClass1).doesNotHaveSameHashCodeAs(testMemberClass1);
+	}
+
+	@Test
+	public void verifyToString() throws Exception {
+		assertThat(get(TestClass.class).toString()).isEqualTo(TestClass.class.getName());
+	}
+
 	@Test
 	public void getClassNameReturnsClassName() {
 		assertThat(get(TestClass.class).getClassName()).isEqualTo(TestClass.class.getName());
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2021 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
@@ -20,7 +20,6 @@ import org.junit.jupiter.api.Test;

 import static org.assertj.core.api.Assertions.assertThat;

-
 /**
 * Abstract base class for testing implementations of
 * {@link ClassMetadata#getMemberClassNames()}.
@@ -30,48 +29,45 @@ import static org.assertj.core.api.Assertions.assertThat;
 */
 public abstract class AbstractClassMetadataMemberClassTests {

-	public abstract ClassMetadata getClassMetadataFor(Class<?> clazz);
+	protected abstract ClassMetadata getClassMetadataFor(Class<?> clazz);

 	@Test
 	void withNoMemberClasses() {
 		ClassMetadata metadata = getClassMetadataFor(L0_a.class);
 		String[] nestedClasses = metadata.getMemberClassNames();
-		assertThat(nestedClasses).isEqualTo(new String[]{});
+		assertThat(nestedClasses).isEmpty();
 	}

-	public static class L0_a {
-	}
-
-
 	@Test
 	void withPublicMemberClasses() {
 		ClassMetadata metadata = getClassMetadataFor(L0_b.class);
 		String[] nestedClasses = metadata.getMemberClassNames();
-		assertThat(nestedClasses).isEqualTo(new String[]{L0_b.L1.class.getName()});
+		assertThat(nestedClasses).containsOnly(L0_b.L1.class.getName());
+	}
+
+	@Test
+	void withNonPublicMemberClasses() {
+		ClassMetadata metadata = getClassMetadataFor(L0_c.class);
+		String[] nestedClasses = metadata.getMemberClassNames();
+		assertThat(nestedClasses).containsOnly(L0_c.L1.class.getName());
+	}
+
+	@Test
+	void againstMemberClass() {
+		ClassMetadata metadata = getClassMetadataFor(L0_b.L1.class);
+		String[] nestedClasses = metadata.getMemberClassNames();
+		assertThat(nestedClasses).isEmpty();
+	}
+
+	public static class L0_a {
 	}

 	public static class L0_b {
 		public static class L1 { }
 	}

-
-	@Test
-	void withNonPublicMemberClasses() {
-		ClassMetadata metadata = getClassMetadataFor(L0_c.class);
-		String[] nestedClasses = metadata.getMemberClassNames();
-		assertThat(nestedClasses).isEqualTo(new String[]{L0_c.L1.class.getName()});
-	}
-
 	public static class L0_c {
 		private static class L1 { }
 	}

-
-	@Test
-	void againstMemberClass() {
-		ClassMetadata metadata = getClassMetadataFor(L0_b.L1.class);
-		String[] nestedClasses = metadata.getMemberClassNames();
-		assertThat(nestedClasses).isEqualTo(new String[]{});
-	}
-
 }
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2020 the original author or authors.
+ * Copyright 2002-2021 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
@@ -37,6 +37,54 @@ import static org.assertj.core.api.Assertions.entry;
 */
 public abstract class AbstractMethodMetadataTests {

+	@Test
+	public void verifyEquals() throws Exception {
+		MethodMetadata withMethod1 = getTagged(WithMethod.class);
+		MethodMetadata withMethod2 = getTagged(WithMethod.class);
+		MethodMetadata withMethodWithTwoArguments1 = getTagged(WithMethodWithTwoArguments.class);
+		MethodMetadata withMethodWithTwoArguments2 = getTagged(WithMethodWithTwoArguments.class);
+
+		assertThat(withMethod1.equals(null)).isFalse();
+
+		assertThat(withMethod1.equals(withMethod1)).isTrue();
+		assertThat(withMethod2.equals(withMethod2)).isTrue();
+		assertThat(withMethod1.equals(withMethod2)).isTrue();
+		assertThat(withMethod2.equals(withMethod1)).isTrue();
+
+		assertThat(withMethodWithTwoArguments1.equals(withMethodWithTwoArguments1)).isTrue();
+		assertThat(withMethodWithTwoArguments2.equals(withMethodWithTwoArguments2)).isTrue();
+		assertThat(withMethodWithTwoArguments1.equals(withMethodWithTwoArguments2)).isTrue();
+		assertThat(withMethodWithTwoArguments2.equals(withMethodWithTwoArguments1)).isTrue();
+
+		assertThat(withMethod1.equals(withMethodWithTwoArguments1)).isFalse();
+		assertThat(withMethodWithTwoArguments1.equals(withMethod1)).isFalse();
+	}
+
+	@Test
+	public void verifyHashCode() throws Exception {
+		MethodMetadata withMethod1 = getTagged(WithMethod.class);
+		MethodMetadata withMethod2 = getTagged(WithMethod.class);
+		MethodMetadata withMethodWithTwoArguments1 = getTagged(WithMethodWithTwoArguments.class);
+		MethodMetadata withMethodWithTwoArguments2 = getTagged(WithMethodWithTwoArguments.class);
+
+		assertThat(withMethod1).hasSameHashCodeAs(withMethod2);
+		assertThat(withMethodWithTwoArguments1).hasSameHashCodeAs(withMethodWithTwoArguments2);
+
+		assertThat(withMethod1).doesNotHaveSameHashCodeAs(withMethodWithTwoArguments1);
+	}
+
+	@Test
+	public void verifyToString() throws Exception {
+		assertThat(getTagged(WithMethod.class).toString())
+			.endsWith(WithMethod.class.getName() + ".test()");
+
+		assertThat(getTagged(WithMethodWithOneArgument.class).toString())
+			.endsWith(WithMethodWithOneArgument.class.getName() + ".test(java.lang.String)");
+
+		assertThat(getTagged(WithMethodWithTwoArguments.class).toString())
+			.endsWith(WithMethodWithTwoArguments.class.getName() + ".test(java.lang.String,java.lang.Integer)");
+	}
+
 	@Test
 	public void getMethodNameReturnsMethodName() {
 		assertThat(getTagged(WithMethod.class).getMethodName()).isEqualTo("test");
@@ -171,6 +219,24 @@ public abstract class AbstractMethodMetadataTests {

 	}

+	public static class WithMethodWithOneArgument {
+
+		@Tag
+		public String test(String text) {
+			return "";
+		}
+
+	}
+
+	public static class WithMethodWithTwoArguments {
+
+		@Tag
+		public String test(String text, Integer num) {
+			return "";
+		}
+
+	}
+
 	public abstract static class WithAbstractMethod {

 		@Tag
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2021 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
@@ -19,6 +19,7 @@ package org.springframework.core.type.classreading;
 import java.io.BufferedInputStream;
 import java.io.InputStream;

+import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;

 import org.springframework.asm.ClassReader;
@@ -35,6 +36,7 @@ import static org.assertj.core.api.Assertions.assertThatExceptionOfType;
 * Tests for {@link AnnotationMetadataReadingVisitor}.
 *
 * @author Phillip Webb
+ * @author Sam Brannen
 */
@SuppressWarnings("deprecation")
 class AnnotationMetadataReadingVisitorTests extends AbstractAnnotationMetadataTests {
@@ -62,11 +64,29 @@ class AnnotationMetadataReadingVisitorTests extends AbstractAnnotationMetadataTe
 		}
 	}

+	@Test
+	@Disabled("equals() not implemented in deprecated AnnotationMetadataReadingVisitor")
+	@Override
+	public void verifyEquals() throws Exception {
+	}
+
+	@Test
+	@Disabled("hashCode() not implemented in deprecated AnnotationMetadataReadingVisitor")
+	@Override
+	public void verifyHashCode() throws Exception {
+	}
+
+	@Test
+	@Disabled("toString() not implemented in deprecated AnnotationMetadataReadingVisitor")
+	@Override
+	public void verifyToString() {
+	}
+
 	@Override
 	@Test
 	public void getAnnotationsReturnsDirectAnnotations() {
-		assertThatExceptionOfType(UnsupportedOperationException.class).isThrownBy(
-				super::getAnnotationsReturnsDirectAnnotations);
+		assertThatExceptionOfType(UnsupportedOperationException.class)
+			.isThrownBy(super::getAnnotationsReturnsDirectAnnotations);
 	}

 }
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2021 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
@@ -19,6 +19,7 @@ package org.springframework.core.type.classreading;
 import java.io.BufferedInputStream;
 import java.io.InputStream;

+import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;

 import org.springframework.asm.ClassReader;
@@ -35,6 +36,7 @@ import static org.assertj.core.api.Assertions.assertThatExceptionOfType;
 * Tests for {@link MethodMetadataReadingVisitor}.
 *
 * @author Phillip Webb
+ * @author Sam Brannen
 */
@SuppressWarnings("deprecation")
 class MethodMetadataReadingVisitorTests extends AbstractMethodMetadataTests {
@@ -62,8 +64,26 @@ class MethodMetadataReadingVisitorTests extends AbstractMethodMetadataTests {
 		}
 	}

-	@Override
 	@Test
+	@Disabled("equals() not implemented in deprecated MethodMetadataReadingVisitor")
+	@Override
+	public void verifyEquals() throws Exception {
+	}
+
+	@Test
+	@Disabled("hashCode() not implemented in deprecated MethodMetadataReadingVisitor")
+	@Override
+	public void verifyHashCode() throws Exception {
+	}
+
+	@Test
+	@Disabled("toString() not implemented in deprecated MethodMetadataReadingVisitor")
+	@Override
+	public void verifyToString() {
+	}
+
+	@Test
+	@Override
 	public void getAnnotationsReturnsDirectAnnotations() {
 		assertThatExceptionOfType(UnsupportedOperationException.class).isThrownBy(
 				super::getAnnotationsReturnsDirectAnnotations);
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2021 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
@@ -194,7 +194,7 @@ class FastByteArrayOutputStreamTests {
 		this.os.write(this.helloBytes);
 		InputStream inputStream = this.os.getInputStream();
 		DigestUtils.appendMd5DigestAsHex(inputStream, builder);
-		builder.append("\"");
+		builder.append('"');
 		String actual = builder.toString();
 		assertThat(actual).isEqualTo("\"0b10a8db164e0754105b7a99be72e3fe5\"");
 	}
@@ -208,7 +208,7 @@ class FastByteArrayOutputStreamTests {
 		}
 		InputStream inputStream = this.os.getInputStream();
 		DigestUtils.appendMd5DigestAsHex(inputStream, builder);
-		builder.append("\"");
+		builder.append('"');
 		String actual = builder.toString();
 		assertThat(actual).isEqualTo("\"06225ca1e4533354c516e74512065331d\"");
 	}
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2021 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
@@ -41,7 +41,7 @@ class StopWatchTests {

 	private static final long duration1 = 200;
 	private static final long duration2 = 100;
-	private static final long fudgeFactor = 50;
+	private static final long fudgeFactor = 100;

 	private final StopWatch stopWatch = new StopWatch(ID);

@@ -107,7 +107,7 @@ class StopWatchTests {
 			.isLessThanOrEqualTo(duration1 + duration2 + fudgeFactor);
 		assertThat(stopWatch.getTotalTimeSeconds())
 			.as("total time in seconds for task #2")
-			.isGreaterThanOrEqualTo((duration1 + duration2  - fudgeFactor) / 1000.0)
+			.isGreaterThanOrEqualTo((duration1 + duration2 - fudgeFactor) / 1000.0)
 			.isLessThanOrEqualTo((duration1 + duration2 + fudgeFactor) / 1000.0);

 		assertThat(stopWatch.getTaskCount()).isEqualTo(2);
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2020 the original author or authors.
+ * Copyright 2002-2021 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
@@ -612,7 +612,7 @@ class StringUtilsTests {
 		StringBuilder sb = new StringBuilder();
 		for (int i = 0; i < components.length; i++) {
 			if (i != 0) {
-				sb.append(",");
+				sb.append(',');
 			}
 			sb.append(components[i]);
 		}
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2021 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
@@ -137,7 +137,7 @@ public class ExpressionException extends RuntimeException {
 			StringBuilder output = new StringBuilder();
 			output.append("Expression [");
 			output.append(this.expressionString);
-			output.append("]");
+			output.append(']');
 			if (this.position >= 0) {
 				output.append(" @");
 				output.append(this.position);
--- a/Show More
+++ b/Show More