Merge branch '6.0.x'

spring-context/src/testFixtures/java/org/springframework/context/testfixture/index/CandidateComponentsTestClassLoader.java

@@ -42,8 +42,7 @@ public class CandidateComponentsTestClassLoader extends ClassLoader {
 	 * @see org.springframework.context.index.CandidateComponentsIndexLoader#COMPONENTS_RESOURCE_LOCATION
 	 */
 	public static ClassLoader disableIndex(ClassLoader classLoader) {
-		return new CandidateComponentsTestClassLoader(classLoader,
-				Collections.enumeration(Collections.emptyList()));
+		return new CandidateComponentsTestClassLoader(classLoader, Collections.emptyEnumeration());
 	}
 
 	/**

spring-test/src/main/java/org/springframework/mock/web/MockHttpServletRequest.java

@@ -1159,7 +1159,8 @@ public class MockHttpServletRequest implements HttpServletRequest {
 	@Override
 	public Enumeration<String> getHeaders(String name) {
 		HeaderValueHolder header = this.headers.get(name);
-		return Collections.enumeration(header != null ? header.getStringValues() : new LinkedList<>());
+		return (header != null ? Collections.enumeration(header.getStringValues()) :
+				Collections.emptyEnumeration());
 	}
 
 	@Override

spring-web/src/testFixtures/java/org/springframework/web/testfixture/servlet/MockHttpServletRequest.java

@@ -1159,7 +1159,8 @@ public class MockHttpServletRequest implements HttpServletRequest {
 	@Override
 	public Enumeration<String> getHeaders(String name) {
 		HeaderValueHolder header = this.headers.get(name);
-		return Collections.enumeration(header != null ? header.getStringValues() : new LinkedList<>());
+		return (header != null ? Collections.enumeration(header.getStringValues()) :
+				Collections.emptyEnumeration());
 	}
 
 	@Override

spring-webmvc/src/main/java/org/springframework/web/servlet/handler/SimpleServletPostProcessor.java

@@ -170,7 +170,7 @@ public class SimpleServletPostProcessor implements
 
 		@Override
 		public Enumeration<String> getInitParameterNames() {
-			return Collections.enumeration(Collections.emptySet());
+			return Collections.emptyEnumeration();
 		}
 	}