--- a/src/share/classes/javax/swing/plaf/nimbus/NimbusLookAndFeel.java	Tue May 24 11:37:09 2011 +0400
+++ b/src/share/classes/javax/swing/plaf/nimbus/NimbusLookAndFeel.java	Sat May 28 11:55:32 2011 +0400
@@ -588,6 +588,10 @@
     }
 
     private void addDefault(String key, Object value) {
+        if (compiledDefaults == null) {
+            return;
+        }
+
         String prefix = parsePrefix(key);
         if (prefix != null) {
             Map<String, Object> keys = compiledDefaults.get(prefix);

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/test/javax/swing/plaf/nimbus/Test7048204.java	Sat May 28 11:55:32 2011 +0400
@@ -0,0 +1,47 @@
+/*
+ * Copyright (c) 2011, 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 7048204
+   @summary NPE from NimbusLookAndFeel.addDefault
+   @author Pavel Porvatov
+*/
+
+import javax.swing.*;
+import javax.swing.plaf.nimbus.NimbusLookAndFeel;
+
+public class Test7048204 {
+    public static void main(String[] args) throws Exception {
+        UIManager.setLookAndFeel(new NimbusLookAndFeel());
+
+        SwingUtilities.invokeAndWait(new Runnable() {
+            public void run() {
+                new JLabel();
+
+                UIDefaults uid = UIManager.getDefaults();
+                uid.putDefaults(new Object[0]);
+                uid.put("what.ever", "else");
+            }
+        });
+    }
+}