Consistent support for EnumSet subclasses in CollectionFactory

Issue: SPR-17619

(cherry picked from commit 31a24720a6)

spring-core/src/main/java/org/springframework/core/CollectionFactory.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2017 the original author or authors.
+ * Copyright 2002-2018 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.
@@ -189,7 +189,7 @@ public abstract class CollectionFactory {
 				throw new IllegalArgumentException("Unsupported Collection interface: " + collectionType.getName());
 			}
 		}
-		else if (EnumSet.class == collectionType) {
+		else if (EnumSet.class.isAssignableFrom(collectionType)) {
 			Assert.notNull(elementType, "Cannot create EnumSet for unknown element type");
 			// Cast is necessary for compilation in Eclipse 4.4.1.
 			return (Collection<E>) EnumSet.noneOf(asEnumType(elementType));