--- a/jdk/src/share/classes/javax/print/attribute/standard/MediaSize.java	Wed Dec 03 13:34:50 2008 +0300
+++ b/jdk/src/share/classes/javax/print/attribute/standard/MediaSize.java	Wed Dec 24 15:48:59 2008 -0800
@@ -123,8 +123,10 @@
         if (x > y) {
             throw new IllegalArgumentException("X dimension > Y dimension");
         }
-        mediaName = media;
-        mediaMap.put(mediaName, this);
+        if (media != null && mediaMap.get(media) == null) {
+            mediaName = media;
+            mediaMap.put(mediaName, this);
+        }
         sizeVector.add(this);
     }
 
@@ -147,8 +149,10 @@
         if (x > y) {
             throw new IllegalArgumentException("X dimension > Y dimension");
         }
-        mediaName = media;
-        mediaMap.put(mediaName, this);
+        if (media != null && mediaMap.get(media) == null) {
+            mediaName = media;
+            mediaMap.put(mediaName, this);
+        }
         sizeVector.add(this);
     }
 

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/test/javax/print/attribute/MediaMappingsTest.java	Wed Dec 24 15:48:59 2008 -0800
@@ -0,0 +1,48 @@
+/*
+ * Copyright 2008 Sun Microsystems, Inc.  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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ */
+
+/*
+ * @test
+ * @bug 6652463
+ * @summary Verify media size-> media mappings can't be altered
+ * @run main MediaMappingsTest
+*/
+
+import javax.print.attribute.standard.MediaSize;
+import javax.print.attribute.standard.MediaSizeName;
+
+public class MediaMappingsTest {
+
+    public static void main(String args[]) {
+        MediaSize sizeA = MediaSize.getMediaSizeForName(MediaSizeName.A);
+        new MediaSize(1.0f, 2.0f, MediaSize.MM, MediaSizeName.A);
+        if (!sizeA.equals(MediaSize.getMediaSizeForName(MediaSizeName.A))) {
+             throw new RuntimeException("mapping changed");
+        }
+        MediaSize sizeB = MediaSize.getMediaSizeForName(MediaSizeName.B);
+        new MediaSize(1, 2, MediaSize.MM, MediaSizeName.B);
+        if (!sizeB.equals(MediaSize.getMediaSizeForName(MediaSizeName.B))) {
+             throw new RuntimeException("mapping changed");
+        }
+    }
+}