--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/src/share/classes/java/io/Externalizable.java	Sat Dec 01 00:00:00 2007 +0000
@@ -0,0 +1,97 @@
+/*
+ * Copyright 1996-2004 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.io;
+
+import java.io.ObjectOutput;
+import java.io.ObjectInput;
+
+/**
+ * Only the identity of the class of an Externalizable instance is
+ * written in the serialization stream and it is the responsibility
+ * of the class to save and restore the contents of its instances.
+ *
+ * The writeExternal and readExternal methods of the Externalizable
+ * interface are implemented by a class to give the class complete
+ * control over the format and contents of the stream for an object
+ * and its supertypes. These methods must explicitly
+ * coordinate with the supertype to save its state. These methods supersede
+ * customized implementations of writeObject and readObject methods.<br>
+ *
+ * Object Serialization uses the Serializable and Externalizable
+ * interfaces.  Object persistence mechanisms can use them as well.  Each
+ * object to be stored is tested for the Externalizable interface. If
+ * the object supports Externalizable, the writeExternal method is called. If the
+ * object does not support Externalizable and does implement
+ * Serializable, the object is saved using
+ * ObjectOutputStream. <br> When an Externalizable object is
+ * reconstructed, an instance is created using the public no-arg
+ * constructor, then the readExternal method called.  Serializable
+ * objects are restored by reading them from an ObjectInputStream.<br>
+ *
+ * An Externalizable instance can designate a substitution object via
+ * the writeReplace and readResolve methods documented in the Serializable
+ * interface.<br>
+ *
+ * @author  unascribed
+ * @see java.io.ObjectOutputStream
+ * @see java.io.ObjectInputStream
+ * @see java.io.ObjectOutput
+ * @see java.io.ObjectInput
+ * @see java.io.Serializable
+ * @since   JDK1.1
+ */
+public interface Externalizable extends java.io.Serializable {
+    /**
+     * The object implements the writeExternal method to save its contents
+     * by calling the methods of DataOutput for its primitive values or
+     * calling the writeObject method of ObjectOutput for objects, strings,
+     * and arrays.
+     *
+     * @serialData Overriding methods should use this tag to describe
+     *             the data layout of this Externalizable object.
+     *             List the sequence of element types and, if possible,
+     *             relate the element to a public/protected field and/or
+     *             method of this Externalizable class.
+     *
+     * @param out the stream to write the object to
+     * @exception IOException Includes any I/O exceptions that may occur
+     */
+    void writeExternal(ObjectOutput out) throws IOException;
+
+    /**
+     * The object implements the readExternal method to restore its
+     * contents by calling the methods of DataInput for primitive
+     * types and readObject for objects, strings and arrays.  The
+     * readExternal method must read the values in the same sequence
+     * and with the same types as were written by writeExternal.
+     *
+     * @param in the stream to read data from in order to restore the object
+     * @exception IOException if I/O errors occur
+     * @exception ClassNotFoundException If the class for an object being
+     *              restored cannot be found.
+     */
+    void readExternal(ObjectInput in) throws IOException, ClassNotFoundException;
+}