From 7a8d41e5d6d4ac85d6d74d80c311800d78e0a721 Mon Sep 17 00:00:00 2001
From: Juergen Hoeller <jhoeller@pivotal.io>
Date: Fri, 30 Mar 2018 13:41:22 +0200
Subject: [PATCH] Extended set of common classes and language interfaces in
 ClassUtils

Issue: SPR-16667
---
 .../org/springframework/util/ClassUtils.java  | 38 ++++++++++++-------
 1 file changed, 24 insertions(+), 14 deletions(-)

diff --git a/spring-core/src/main/java/org/springframework/util/ClassUtils.java b/spring-core/src/main/java/org/springframework/util/ClassUtils.java
index 33bf4bbf3cd..52853dd19ad 100644
--- a/spring-core/src/main/java/org/springframework/util/ClassUtils.java
+++ b/spring-core/src/main/java/org/springframework/util/ClassUtils.java
@@ -17,6 +17,7 @@
 package org.springframework.util;
 
 import java.beans.Introspector;
+import java.io.Closeable;
 import java.io.Externalizable;
 import java.io.Serializable;
 import java.lang.reflect.Array;
@@ -27,12 +28,15 @@ import java.lang.reflect.Proxy;
 import java.util.Arrays;
 import java.util.Collection;
 import java.util.Collections;
+import java.util.Enumeration;
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.IdentityHashMap;
 import java.util.Iterator;
 import java.util.LinkedHashSet;
+import java.util.List;
 import java.util.Map;
+import java.util.Optional;
 import java.util.Set;
 
 import org.springframework.lang.Nullable;
@@ -76,13 +80,6 @@ public abstract class ClassUtils {
 	public static final String CLASS_FILE_SUFFIX = ".class";
 
 
-	/**
-	 * Common Java language interfaces which are supposed to be ignored
-	 * when searching for 'primary' user-level interfaces.
-	 */
-	private static final Set<Class<?>> javaLanguageInterfaces = new HashSet<>(
-			Arrays.asList(Serializable.class, Externalizable.class, Cloneable.class, Comparable.class));
-
 	/**
 	 * Map with primitive wrapper type as key and corresponding primitive
 	 * type as value, for example: Integer.class -> int.class.
@@ -102,10 +99,16 @@ public abstract class ClassUtils {
 	private static final Map<String, Class<?>> primitiveTypeNameMap = new HashMap<>(32);
 
 	/**
-	 * Map with common "java.lang" class name as key and corresponding Class as value.
+	 * Map with common Java language class name as key and corresponding Class as value.
 	 * Primarily for efficient deserialization of remote invocations.
 	 */
-	private static final Map<String, Class<?>> commonClassCache = new HashMap<>(32);
+	private static final Map<String, Class<?>> commonClassCache = new HashMap<>(64);
+
+	/**
+	 * Common Java language interfaces which are supposed to be ignored
+	 * when searching for 'primary' user-level interfaces.
+	 */
+	private static final Set<Class<?>> javaLanguageInterfaces;
 
 
 	static {
@@ -135,9 +138,16 @@ public abstract class ClassUtils {
 		registerCommonClasses(Boolean[].class, Byte[].class, Character[].class, Double[].class,
 				Float[].class, Integer[].class, Long[].class, Short[].class);
 		registerCommonClasses(Number.class, Number[].class, String.class, String[].class,
-				Object.class, Object[].class, Class.class, Class[].class);
+				Class.class, Class[].class, Object.class, Object[].class);
 		registerCommonClasses(Throwable.class, Exception.class, RuntimeException.class,
 				Error.class, StackTraceElement.class, StackTraceElement[].class);
+		registerCommonClasses(Enum.class, Iterable.class, Iterator.class, Enumeration.class,
+				Collection.class, List.class, Set.class, Map.class, Map.Entry.class, Optional.class);
+
+		Class<?>[] javaLanguageInterfaceArray = {Serializable.class, Externalizable.class,
+				Closeable.class, AutoCloseable.class, Cloneable.class, Comparable.class};
+		registerCommonClasses(javaLanguageInterfaceArray);
+		javaLanguageInterfaces = new HashSet<>(Arrays.asList(javaLanguageInterfaceArray));
 	}
 
 
@@ -1235,10 +1245,10 @@ public abstract class ClassUtils {
 
 	/**
 	 * Determine whether the given interface is a common Java language interface:
-	 * {@link Serializable}, {@link Externalizable}, {@link Cloneable}, {@link Comparable}
-	 * - all of which can be ignored when looking for 'primary' user-level interfaces.
-	 * Common characteristics: no service-level operations, no bean property methods,
-	 * no default methods.
+	 * {@link Serializable}, {@link Externalizable}, {@link Closeable}, {@link AutoCloseable},
+	 * {@link Cloneable}, {@link Comparable} - all of which can be ignored when looking
+	 * for 'primary' user-level interfaces. Common characteristics: no service-level
+	 * operations, no bean property methods, no default methods.
 	 * @param ifc the interface to check
 	 * @since 5.0.3
 	 */