LinkedCaseInsensitiveMap properly overrides HashMap.clone()

Issue: SPR-14509
(cherry picked from commit dadd2c37)

spring-core/src/main/java/org/springframework/util/LinkedCaseInsensitiveMap.java

 /*
- * 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.
@@ -36,7 +36,7 @@ import java.util.Map;
 @SuppressWarnings("serial")
 public class LinkedCaseInsensitiveMap<V> extends LinkedHashMap<String, V> {
 
-	private final Map<String, String> caseInsensitiveKeys;
+	private Map<String, String> caseInsensitiveKeys;
 
 	private final Locale locale;
 
@@ -114,21 +114,23 @@ public class LinkedCaseInsensitiveMap<V> extends LinkedHashMap<String, V> {
 	@Override
 	public V get(Object key) {
 		if (key instanceof String) {
-			return super.get(this.caseInsensitiveKeys.get(convertKey((String) key)));
-		}
-		else {
-			return null;
+			String caseInsensitiveKey = this.caseInsensitiveKeys.get(convertKey((String) key));
+			if (caseInsensitiveKey != null) {
+				return super.get(caseInsensitiveKey);
+			}
 		}
+		return null;
 	}
 
 	@Override
 	public V remove(Object key) {
-		if (key instanceof String ) {
-			return super.remove(this.caseInsensitiveKeys.remove(convertKey((String) key)));
-		}
-		else {
-			return null;
+		if (key instanceof String) {
+			String caseInsensitiveKey = this.caseInsensitiveKeys.remove(convertKey((String) key));
+			if (caseInsensitiveKey != null) {
+				return super.remove(caseInsensitiveKey);
+			}
 		}
+		return null;
 	}
 
 	@Override
@@ -137,6 +139,14 @@ public class LinkedCaseInsensitiveMap<V> extends LinkedHashMap<String, V> {
 		super.clear();
 	}
 
+	@Override
+	@SuppressWarnings("unchecked")
+	public Object clone() {
+		LinkedCaseInsensitiveMap<V> copy = (LinkedCaseInsensitiveMap<V>) super.clone();
+		copy.caseInsensitiveKeys = new HashMap<String, String>(this.caseInsensitiveKeys);
+		return copy;
+	}
+
 
 	/**
 	 * Convert the given key to a case-insensitive key.

spring-core/src/test/java/org/springframework/util/LinkedCaseInsensitiveMapTests.java

 /*
- * 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.
@@ -16,7 +16,6 @@
 
 package org.springframework.util;
 
-import org.junit.Before;
 import org.junit.Test;
 
 import static org.junit.Assert.*;
@@ -26,12 +25,8 @@ import static org.junit.Assert.*;
  */
 public class LinkedCaseInsensitiveMapTests {
 
-	private LinkedCaseInsensitiveMap<String> map;
+	private final LinkedCaseInsensitiveMap<String> map = new LinkedCaseInsensitiveMap<String>();
 
-	@Before
-	public void setUp() {
-		map = new LinkedCaseInsensitiveMap<String>();
-	}
 
 	@Test
 	public void putAndGet() {
@@ -55,4 +50,26 @@ public class LinkedCaseInsensitiveMapTests {
 		assertEquals("value3", map.get("Key"));
 	}
 
+	@Test
+	@SuppressWarnings("unchecked")
+	public void mapClone() {
+		map.put("key", "value1");
+		LinkedCaseInsensitiveMap<String> copy = (LinkedCaseInsensitiveMap<String>) map.clone();
+		assertEquals("value1", map.get("key"));
+		assertEquals("value1", map.get("KEY"));
+		assertEquals("value1", map.get("Key"));
+		assertEquals("value1", copy.get("key"));
+		assertEquals("value1", copy.get("KEY"));
+		assertEquals("value1", copy.get("Key"));
+		copy.put("Key", "value2");
+		assertEquals(1, map.size());
+		assertEquals(1, copy.size());
+		assertEquals("value1", map.get("key"));
+		assertEquals("value1", map.get("KEY"));
+		assertEquals("value1", map.get("Key"));
+		assertEquals("value2", copy.get("key"));
+		assertEquals("value2", copy.get("KEY"));
+		assertEquals("value2", copy.get("Key"));
+	}
+
 }