--- a/jdk/src/share/classes/java/text/RuleBasedCollator.java	Thu Oct 07 18:23:13 2010 +0400
+++ b/jdk/src/share/classes/java/text/RuleBasedCollator.java	Fri Oct 08 09:50:56 2010 +0900
@@ -335,9 +335,15 @@
      * collation rules.  Returns information about whether a string is less
      * than, greater than or equal to another string in a language.
      * This can be overriden in a subclass.
+     *
+     * @exception NullPointerException if <code>source</code> or <code>target</code> is null.
      */
     public synchronized int compare(String source, String target)
     {
+        if (source == null || target == null) {
+            throw new NullPointerException();
+        }
+
         // The basic algorithm here is that we use CollationElementIterators
         // to step through both the source and target strings.  We compare each
         // collation element in the source string against the corresponding one

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/test/java/text/Collator/Bug6970930.java	Fri Oct 08 09:50:56 2010 +0900
@@ -0,0 +1,78 @@
+/*
+ * Copyright (c) 2010, 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 6970930
+ * @summary verify that compare() throws NPE instead of IAE when an argument is null.
+ */
+import java.text.*;
+
+public class Bug6970930 {
+
+    private static boolean err = false;
+
+    public static void main(String[] args) {
+        // Check if compare() throws NPE.
+        test1(null, null);
+        test1("\"foo\"", null);
+        test1(null, "\"bar\"");
+
+        if (err) {
+            throw new RuntimeException("Failed.");
+        } else {
+            System.out.println("Passed.");
+        }
+    }
+
+    private static void test1(String s1, String s2) {
+        RuleBasedCollator col = null;
+
+        try {
+            col = new RuleBasedCollator("< a < b");
+        }
+        catch (ParseException e) {
+            err = true;
+            System.err.println(e);
+        }
+
+        try {
+            col.compare("foo", "bar"); // This line is necessary to reproduce the bug.
+            col.compare(s1, s2);
+
+            err = true;
+            System.err.println("No exception was thrown for compare(" +
+                               s1 + ", " +  s2 + ").");
+        }
+        catch (NullPointerException e) {
+            System.out.println("NPE was thrown as expected for compare(" +
+                               s1 + ", " + s2 + ").");
+        }
+        catch (Exception e) {
+            err = true;
+            System.err.println("Unexpected exception was thrown for compare(" +
+                               s1 + ", " + s2 + "): " + e);
+        }
+    }
+
+}