[Bug java/12647] New: wait() bug on Win32

[mkaufmann at student dot ethz dot ch]

PLEASE REPLY TO gcc-bugzilla@gcc.gnu.org ONLY, *NOT* gcc-bugs@gcc.gnu.org.

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=12647

           Summary: wait() bug on Win32
           Product: gcc
           Version: 3.3.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: java
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: mkaufmann at student dot ethz dot ch
                CC: gcc-bugs at gcc dot gnu dot org

On Windows (I used the MinGW version 3.3.1 of gcj), there's a bug if a
synchronized method calls wait(). If the method containing wait() was invoked by
another synchronized method of the same object, then the calling thread keeps
the lock on this object.

Example program:

If you run this with the Java 1.4.1 VM on Windows, the output is

a
c
c
c
...


If compiled with GCJ on Windows, the output is only

a


Code of the example program:

public class Test
{
  public static void main(String args[])
  {
    Test test = new Test();

    new MyThread(test).start();

    while(true)
    {
      try
      {
        Thread.sleep(1000);
      }
      catch (Exception e)
      {
        e.printStackTrace();
      }

      test.c();
    }
  }

  public synchronized void a()
  {
    System.out.println("a");

    b();
  }

  public synchronized void b()
  {
    try
    {
      wait();
    }
    catch (Exception e)
    {
      e.printStackTrace();
    }

    System.out.println("b");
  }

  public synchronized void c()
  {
    System.out.println("c");
  }
}


class MyThread extends Thread
{
  private Test test;

  public MyThread(Test test)
  {
    this.test = test;
  }

  public void run()
  {
    test.a();
  }
}