jdk/test/java/io/Serializable/replaceWithNull/ReplaceWithNull.java

/*
 * Copyright 1997-1998 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.
 *
 * 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 4065313
 * @clean A ReplaceWithNull MyObjectOutputStream
 * @summary Ensure that it is okay to replace an object with null.
 */
import java.io.*;

class A { }

class MyObjectOutputStream extends ObjectOutputStream {
  public MyObjectOutputStream(OutputStream out) throws IOException {
    super(out);
    enableReplaceObject(true);
  }
  protected Object replaceObject(Object obj) throws IOException {
    if(obj instanceof A) return null;
    else return obj;
  }
}

public class ReplaceWithNull {
    public static void main(String args[]) throws IOException {
        A a = new A();

        MyObjectOutputStream out =
            new MyObjectOutputStream(new ByteArrayOutputStream());
        out.writeObject(a);     //raised NullPointerException.
        out.close();
    }
}