Consistently use DefaultParameterNameDiscoverer.getSharedInstance()

This includes MethodParameter resolving getParameterName() by default now.
initParameterNameDiscovery(null) can be used to suppress such resolution.

Closes gh-36024

spring-context/src/main/java/org/springframework/cache/interceptor/CacheEvaluationContextFactory.java

@@ -39,21 +39,24 @@ class CacheEvaluationContextFactory {
 
 	private @Nullable Supplier<ParameterNameDiscoverer> parameterNameDiscoverer;
 
+
 	CacheEvaluationContextFactory(StandardEvaluationContext originalContext) {
 		this.originalContext = originalContext;
 	}
 
+
 	public void setParameterNameDiscoverer(Supplier<ParameterNameDiscoverer> parameterNameDiscoverer) {
 		this.parameterNameDiscoverer = parameterNameDiscoverer;
 	}
 
 	public ParameterNameDiscoverer getParameterNameDiscoverer() {
 		if (this.parameterNameDiscoverer == null) {
-			this.parameterNameDiscoverer = SingletonSupplier.of(new DefaultParameterNameDiscoverer());
+			this.parameterNameDiscoverer = SingletonSupplier.of(DefaultParameterNameDiscoverer.getSharedInstance());
 		}
 		return this.parameterNameDiscoverer.get();
 	}
 
+
 	/**
 	 * Creates a {@link CacheEvaluationContext} for the specified operation.
 	 * @param rootObject the {@code root} object to use for the context

spring-context/src/main/java/org/springframework/context/expression/CachedExpressionEvaluator.java

@@ -38,8 +38,6 @@ public abstract class CachedExpressionEvaluator {
 
 	private final SpelExpressionParser parser;
 
-	private final ParameterNameDiscoverer parameterNameDiscoverer = new DefaultParameterNameDiscoverer();
-
 
 	/**
 	 * Create a new instance with the default {@link SpelExpressionParser}.
@@ -69,7 +67,7 @@ public abstract class CachedExpressionEvaluator {
 	 * @since 4.3
 	 */
 	protected ParameterNameDiscoverer getParameterNameDiscoverer() {
-		return this.parameterNameDiscoverer;
+		return DefaultParameterNameDiscoverer.getSharedInstance();
 	}
 
 	/**

spring-context/src/main/java/org/springframework/jmx/export/assembler/AbstractReflectiveMBeanInfoAssembler.java

@@ -183,7 +183,8 @@ public abstract class AbstractReflectiveMBeanInfoAssembler extends AbstractMBean
 
 	private boolean exposeClassDescriptor = false;
 
-	private @Nullable ParameterNameDiscoverer parameterNameDiscoverer = new DefaultParameterNameDiscoverer();
+	private @Nullable ParameterNameDiscoverer parameterNameDiscoverer =
+			DefaultParameterNameDiscoverer.getSharedInstance();
 
 
 	/**
@@ -507,8 +508,8 @@ public abstract class AbstractReflectiveMBeanInfoAssembler extends AbstractMBean
 	 * @return the {@code MBeanParameterInfo} array
 	 */
 	protected MBeanParameterInfo[] getOperationParameters(Method method, String beanKey) {
-		ParameterNameDiscoverer paramNameDiscoverer = getParameterNameDiscoverer();
-		@Nullable String[] paramNames = (paramNameDiscoverer != null ? paramNameDiscoverer.getParameterNames(method) : null);
+		ParameterNameDiscoverer pnd = getParameterNameDiscoverer();
+		@Nullable String[] paramNames = (pnd != null ? pnd.getParameterNames(method) : null);
 		if (paramNames == null) {
 			return new MBeanParameterInfo[0];
 		}

spring-context/src/main/java/org/springframework/validation/beanvalidation/MethodValidationAdapter.java

@@ -87,7 +87,7 @@ public class MethodValidationAdapter implements MethodValidator {
 
 	private MessageCodesResolver messageCodesResolver = new DefaultMessageCodesResolver();
 
-	private ParameterNameDiscoverer parameterNameDiscoverer = new DefaultParameterNameDiscoverer();
+	private ParameterNameDiscoverer parameterNameDiscoverer = DefaultParameterNameDiscoverer.getSharedInstance();
 
 	private ObjectNameResolver objectNameResolver = defaultObjectNameResolver;