Add @FunctionalInterface on candidate interfaces

Issue: SPR-14432

spring-context/src/main/java/org/springframework/cache/Cache.java

@@ -145,6 +145,7 @@ public interface Cache {
 	/**
 	 * A (wrapper) object representing a cache value.
 	 */
+	@FunctionalInterface
 	interface ValueWrapper {
 
 		/**

spring-context/src/main/java/org/springframework/cache/annotation/AnnotationCacheOperationSource.java

@@ -181,6 +181,7 @@ public class AnnotationCacheOperationSource extends AbstractFallbackCacheOperati
 	 * Callback interface providing {@link CacheOperation} instance(s) based on
 	 * a given {@link CacheAnnotationParser}.
 	 */
+	@FunctionalInterface
 	protected interface CacheOperationProvider {
 
 		/**

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

@@ -27,6 +27,7 @@ package org.springframework.cache.interceptor;
  * @author Stephane Nicoll
  * @since 4.1
  */
+@FunctionalInterface
 public interface CacheOperationInvoker {
 
 	/**

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2015 the original author or authors.
+ * Copyright 2002-2016 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.cache.Cache;
  * @author Stephane Nicoll
  * @since 4.1
  */
+@FunctionalInterface
 public interface CacheResolver {
 
 	/**

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2013 the original author or authors.
+ * Copyright 2002-2016 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.
@@ -27,6 +27,7 @@ import java.lang.reflect.Method;
  * @author Phillip Webb
  * @since 3.1
  */
+@FunctionalInterface
 public interface KeyGenerator {
 
 	/**

spring-context/src/main/java/org/springframework/context/ApplicationListener.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2015 the original author or authors.
+ * Copyright 2002-2016 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.
@@ -33,6 +33,7 @@ import java.util.EventListener;
  * @param <E> the specific ApplicationEvent subclass to listen to
  * @see org.springframework.context.event.ApplicationEventMulticaster
  */
+@FunctionalInterface
 public interface ApplicationListener<E extends ApplicationEvent> extends EventListener {
 
 	/**

spring-context/src/main/java/org/springframework/context/annotation/Condition.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2013 the original author or authors.
+ * Copyright 2002-2016 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.
@@ -38,6 +38,7 @@ import org.springframework.core.type.AnnotatedTypeMetadata;
  * @see Conditional
  * @see ConditionContext
  */
+@FunctionalInterface
 public interface Condition {
 
 	/**

spring-context/src/main/java/org/springframework/context/annotation/ConfigurationClassEnhancer.java

@@ -151,6 +151,7 @@ class ConfigurationClassEnhancer {
 	 * must remain public in order to allow access to subclasses generated from other
 	 * packages (i.e. user code).
 	 */
+	@FunctionalInterface
 	public interface EnhancedConfiguration extends BeanFactoryAware {
 	}
 
@@ -159,6 +160,7 @@ class ConfigurationClassEnhancer {
 	 * Conditional {@link Callback}.
 	 * @see ConditionalCallbackFilter
 	 */
+	@FunctionalInterface
 	private interface ConditionalCallback extends Callback {
 
 		boolean isMatch(Method candidateMethod);

spring-context/src/main/java/org/springframework/context/annotation/ScopeMetadataResolver.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2012 the original author or authors.
+ * Copyright 2002-2016 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.
@@ -25,6 +25,7 @@ import org.springframework.beans.factory.config.BeanDefinition;
  * @since 2.5
  * @see org.springframework.context.annotation.Scope
  */
+@FunctionalInterface
 public interface ScopeMetadataResolver {
 
 	/**

spring-context/src/main/java/org/springframework/format/Parser.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2012 the original author or authors.
+ * Copyright 2002-2016 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.
@@ -26,6 +26,7 @@ import java.util.Locale;
  * @since 3.0
  * @param <T> the type of object this Parser produces
  */
+@FunctionalInterface
 public interface Parser<T> {
 
 	/**

spring-context/src/main/java/org/springframework/format/Printer.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2012 the original author or authors.
+ * Copyright 2002-2016 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.
@@ -25,6 +25,7 @@ import java.util.Locale;
  * @since 3.0
  * @param <T> the type of object this Printer prints
  */
+@FunctionalInterface
 public interface Printer<T> {
 
 	/**

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

@@ -1077,7 +1077,8 @@ public class MBeanExporter extends MBeanRegistrationSupport implements MBeanExpo
 	/**
 	 * Internal callback interface for the autodetection process.
 	 */
-	private static interface AutodetectCallback {
+	@FunctionalInterface
+	private interface AutodetectCallback {
 
 		/**
 		 * Called during the autodetection process to decide whether

spring-context/src/main/java/org/springframework/jmx/export/naming/ObjectNamingStrategy.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2012 the original author or authors.
+ * Copyright 2002-2016 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.
@@ -30,6 +30,7 @@ import javax.management.ObjectName;
  * @see org.springframework.jmx.export.MBeanExporter
  * @see javax.management.ObjectName
  */
+@FunctionalInterface
 public interface ObjectNamingStrategy {
 
 	/**

spring-context/src/main/java/org/springframework/jmx/export/notification/NotificationPublisher.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2012 the original author or authors.
+ * Copyright 2002-2016 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.
@@ -42,6 +42,7 @@ import javax.management.Notification;
  * @see NotificationPublisherAware
  * @see org.springframework.jmx.export.MBeanExporter
  */
+@FunctionalInterface
 public interface NotificationPublisher {
 
 	/**

spring-context/src/main/java/org/springframework/jndi/JndiCallback.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2012 the original author or authors.
+ * Copyright 2002-2016 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.
@@ -33,6 +33,7 @@ import javax.naming.NamingException;
  * @see JndiTemplate
  * @see org.springframework.jdbc.core.JdbcTemplate
  */
+@FunctionalInterface
 public interface JndiCallback<T> {
 
 	/**

spring-context/src/main/java/org/springframework/scheduling/annotation/SchedulingConfigurer.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2012 the original author or authors.
+ * Copyright 2002-2016 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.scheduling.config.ScheduledTaskRegistrar;
  * @see EnableScheduling
  * @see ScheduledTaskRegistrar
  */
+@FunctionalInterface
 public interface SchedulingConfigurer {
 
 	/**

spring-context/src/main/java/org/springframework/scripting/groovy/GroovyObjectCustomizer.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2012 the original author or authors.
+ * Copyright 2002-2016 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.
@@ -30,6 +30,7 @@ import groovy.lang.GroovyObject;
  * @since 2.0.2
  * @see GroovyScriptFactory
  */
+@FunctionalInterface
 public interface GroovyObjectCustomizer {
 
 	/**