/*

 * Copyright 2005 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 4905777

   @summary PrintWriter.println(Object) oversynchronized, can deadlock

*/

import java.io.PrintWriter;

public class OversynchronizedTest extends Thread {

    private static PrintWriter writer = new PrintWriter(System.out);

    private static TestObj testObj = new TestObj("This is a test.", writer);

    private static int loopNum = 100;

    public void run() {

        for(int i=0; i<loopNum; i++) {

            testObj.test();

            //passing an object to PrintWriter.println might cause deadlock

            //if the object has a synchronized toString() method.

            //using PrintWriter.println(testObj.toString()) won't have a problem

           writer.println(testObj);

        }

    }

    public static void main(String args[]) throws Exception {

        // should no NullPointerException

        writer.println((Object)null);

        int num = 5;

        OversynchronizedTest[] t = new OversynchronizedTest[num];

        for(int i=0; i<num; i++) {

            t[i] = new OversynchronizedTest();

            t[i].start();

        }

        for(int i=0; i <num; i++) {

            t[i].join();

        }

        System.out.println("Test completed");

    }

}

class TestObj {

    String mStr;

    TestObj(String str, PrintWriter writer) {

        mStr = str;

        this.writer = writer;

    }

    synchronized void test() {

        try {

            long t = Math.round(Math.random()*10);

            Thread.currentThread().sleep(t);

        } catch (InterruptedException e) {

            // jtreg timeout?

            // Only jtreg will interrupt this thread so it knows what to do:

            e.printStackTrace();

        }

        //the following line might cause hang if there is PrintWriter.println(testObj)

        //called by other threads.

        writer.println("In test().");

    }

    synchronized public String toString() {

        writer.println("Calling toString\n");

        return mStr;

    }

    private PrintWriter writer;

}