8040076: Memory leak. java.awt.List objects allowing multiple selections are not GC-ed.

Reviewed-by: anthony, pchelko
Contributed-by: artem.malenko@oracle.com

src/windows/native/sun/windows/awt_Component.cpp

@@ -492,7 +492,12 @@ AwtComponent::CreateHWnd(JNIEnv *env, LPCWSTR title,
      * member is referred in the GetClassName method of AwtLabel class.
      * So m_peerObject member must be set here.
      */
-    m_peerObject = env->NewGlobalRef(peer);
+    if (m_peerObject == NULL) {
+        m_peerObject = env->NewGlobalRef(peer);
+    } else {
+        assert(env->IsSameObject(m_peerObject, peer));
+    }
+
     RegisterClass();
 
     jobject target = env->GetObjectField(peer, AwtObject::targetID);

test/java/awt/List/ListGarbageCollectionTest/AwtListGarbageCollectionTest.java

+/*
+ * Copyright (c) 2014, 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 8040076
+ * @summary AwtList not garbage collected
+ * @run main/othervm -Xmx100m AwtListGarbageCollectionTest
+ */
+
+import java.awt.*;
+import java.awt.event.WindowAdapter;
+import java.awt.event.WindowEvent;
+import java.lang.ref.WeakReference;
+
+public class AwtListGarbageCollectionTest {
+    public static void main(String[] args) {
+        Frame frame = new Frame("List leak test");
+        try {
+            test(frame);
+        } finally {
+            frame.dispose();
+        }
+    }
+
+    private static void test(Frame frame) {
+        WeakReference<List> weakListRef = null;
+        try {
+            frame.setSize(300, 200);
+            frame.setVisible(true);
+
+            List strongListRef = new List();
+            frame.add(strongListRef);
+            strongListRef.setMultipleMode(true);
+            frame.remove(strongListRef);
+            weakListRef = new WeakReference<List>(strongListRef);
+            strongListRef = null;
+
+            //make out of memory to force gc
+            String veryLongString = new String(new char[100]);
+            while (true) {
+                veryLongString += veryLongString;
+            }
+        } catch (OutOfMemoryError e) {
+            if (weakListRef == null) {
+                throw new RuntimeException("Weak list ref wasn't created");
+            } else if (weakListRef.get() != null) {
+                throw new RuntimeException("List wasn't garbage collected");
+            }
+        }
+    }
+}