7144488: Infinite recursion for some equals tests in Collections

Reviewed-by: alanb, dholmes, mduigou

src/share/classes/java/util/Collections.java

 /*
- * Copyright (c) 1997, 2011, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1997, 2012, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -1489,6 +1489,8 @@ public class Collections {
                 }
                 public int hashCode()    {return e.hashCode();}
                 public boolean equals(Object o) {
+                    if (this == o)
+                        return true;
                     if (!(o instanceof Map.Entry))
                         return false;
                     Map.Entry t = (Map.Entry)o;
@@ -1709,6 +1711,8 @@ public class Collections {
         }
 
         public boolean equals(Object o) {
+            if (this == o)
+                return true;
             synchronized (mutex) {return c.equals(o);}
         }
         public int hashCode() {
@@ -1863,6 +1867,8 @@ public class Collections {
         }
 
         public boolean equals(Object o) {
+            if (this == o)
+                return true;
             synchronized (mutex) {return list.equals(o);}
         }
         public int hashCode() {
@@ -2073,6 +2079,8 @@ public class Collections {
         }
 
         public boolean equals(Object o) {
+            if (this == o)
+                return true;
             synchronized (mutex) {return m.equals(o);}
         }
         public int hashCode() {

test/java/util/Collections/EqualsTest.java

+/*
+ * Copyright (c) 2012, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/*
+ * @test
+ * @bug 7144488
+ * @summary Infinite recursion for some equals tests in Collections
+ */
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+
+public class EqualsTest {
+    public static void main(String[] args) {
+        boolean test;
+
+        /* synchronizedList test */
+        List list = Collections.synchronizedList(new ArrayList());
+        list.add(list);
+        test = list.equals(list);
+        assertTrue(test);
+        list.remove(list);
+
+        /* synchronizedSet test */
+        Set s = Collections.synchronizedSet(new HashSet());
+        s.add(s);
+        test = s.equals(s);
+        assertTrue(test);
+
+        /* synchronizedMap test */
+        Map m =  Collections.synchronizedMap(new HashMap());
+        test = m.equals(m);
+        assertTrue(test);
+
+    }
+
+    private static void assertTrue(boolean b) {
+        if (!b)
+            throw new RuntimeException("assertion failed");
+    }
+}
+