diff -r fd16c54261b3 -r 90ce3da70b43 jdk/src/share/classes/java/util/Observer.java
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/src/share/classes/java/util/Observer.java	Sat Dec 01 00:00:00 2007 +0000
@@ -0,0 +1,47 @@
+/*
+ * Copyright 1994-1998 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.  Sun designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Sun in the LICENSE file that accompanied this code.
+ *
+ * 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.
+ */
+package java.util;
+
+/**
+ * A class can implement the <code>Observer</code> interface when it
+ * wants to be informed of changes in observable objects.
+ *
+ * @author  Chris Warth
+ * @see     java.util.Observable
+ * @since   JDK1.0
+ */
+public interface Observer {
+    /**
+     * This method is called whenever the observed object is changed. An
+     * application calls an <tt>Observable</tt> object's
+     * <code>notifyObservers</code> method to have all the object's
+     * observers notified of the change.
+     *
+     * @param   o     the observable object.
+     * @param   arg   an argument passed to the <code>notifyObservers</code>
+     *                 method.
+     */
+    void update(Observable o, Object arg);
+}