Name: skT45625 Date: 11/06/2000


java version "1.3.0"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.3.0)
Java HotSpot(TM) Client VM (build 1.3.0, mixed mode)

ServerSocket.accept does not notice thread interrupts or closes of the
socket:

The code:

import java.net.*;
import java.io.*;
import java.util.*;
public class CloseTest extends Thread
{
    ServerSocket socket;

    public void run()
    {
        long start = System.currentTimeMillis();
        try
        {
            socket = new ServerSocket(8080);
            socket.setSoTimeout(20000);
            System.err.println("Socket="+socket+" accepting...");
            socket.accept();
        }
        catch(Exception e) {e.printStackTrace();}
        finally
        {
            if (System.currentTimeMillis()-start > 19000 )
                System.err.println("TOOK TOO LONG TO NOTICE THE INTERRUPT AND/OR
CLOSE!!!");
        }
    }

    public static void main(String[] arg)
    {
        try
        {
            CloseTest ct=new CloseTest();
            ct.start();
            Thread.sleep(1000);
            ct.interrupt();
            ct.socket.close();
        }
        catch(Exception e) {e.printStackTrace();}
    }
}


produces the following output:

Socket=ServerSocket[addr=0.0.0.0/0.0.0.0,port=0,localport=8080] accepting...
java.net.SocketException: Socket closed
at java.net.PlainSocketImpl.socketAccept(Native Method)
at java.net.PlainSocketImpl.accept(PlainSocketImpl.java:413)
at java.net.ServerSocket.implAccept(ServerSocket.java:243)
at java.net.ServerSocket.accept(ServerSocket.java:222)
at CloseTest.run(CloseTest.java:19)
TOOK TOO LONG TO NOTICE THE INTERRUPT AND/OR CLOSE!!!
(Review ID: 111881)
======================================================================

Name: krC82822 Date: 11/09/2000


9 Nov 2000, eval1127@eng -- recently re-opened as # 4386498.
---------------

java version "1.3.0"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.3.0)
Java HotSpot(TM) Client VM (build 1.3.0, mixed mode)

This bug looks same as bug ID 4107121. When a ServerSocket is waiting in
accept() on a thread (thread-1), close() on another thread (thread-2) should
close the ServerSocket and cause an IOException on thread-2, but on JDK1.3 for
Linux, close() doesn't take effect; server socket isn't closed.

I tested this with JDK1.2.2_006, JDK1.3.0rc1 and JDK1.3.0. 1.2.2 doesn't have
this probrem. 1.3.0 has it on both of mixed / interpreted mode.

  To reproduce, just run following program. On JDK1.2.2, an IOException is raised
when close() is called, but no responce can be seen on 1.3.

import java.net.*;
import java.io.*;

public class Test {
  PrintStream out = System.out;
^Z^Z
  class ServerThread extends Thread {
    ServerSocket serverSocket = null;
    void println(String mes) {
      out.println("SVR: " + mes);
      out.flush();
    }
    public ServerThread() {
      super("ServerThread");
    }
    public void run() {
      println("server thread started.");
      try {
        println("creating server socket...");
        serverSocket = new ServerSocket(2222);
        println("...server socket created.");

        println("starting accept...");
        Socket clientSocket = serverSocket.accept();
        println("...accept finished.");

        println("closing client socket...");
        clientSocket.close();
        println("...client socket closed.");

        println("closing server socket...");
        serverSocket.close();
        println("...server socket closed.");

      }
      catch (IOException ex) {
        println("ERROR ::");
        ex.printStackTrace(out);
        out.flush();
      }
      println("server thread finished.");
    }
  }
  void println(String mes) {
    out.println(mes);
    out.flush();
  }
  public void doit() throws Exception {
    ServerThread server = new ServerThread();
    server.start();
    Thread.currentThread().sleep(1500);
    println("closing server socket...");
    server.serverSocket.close();
    println("...server socket closed.");
    Thread.currentThread().sleep(1500);
  }
  public static void main(String[] args) throws Exception {
    Test t = new Test();
    t.doit();
  }
}
(Review ID: 110961)
======================================================================

Name: krC82822 Date: 11/09/2000


Note: if you use jdk1.2.2 from blackdown, there is no bug but if you use either
IBM jdk1.3 or SUN jdk1.3 there is a bug.......
Also Note: It all works under windows (jdk1.3)

Hint: maybe some synchronized code in native impl of Socket (there seems to have
been a similar bug in the past: blocking socket methods and close methods were
synchronized)

Now here is the code:

import java.io.*;
import java.net.*;

public
class Bug
{
    //--------------------------------------------------------------------
    // public
    //--------------------------------------------------------------------
    public Bug()
    {
        theAcceptingThread = new Thread("acceptor")
        {
            public void
            run()
            {
                try
                {
                    theSocket = new ServerSocket(1234);
                    theSocket.accept();
                }
                catch (IOException anException)
                {
                    System.out.println("ok, this is what should happen " +
                        "when there is no bug....");
                    anException.printStackTrace();
                }
            }
        };

        theClosingThread = new Thread("closer")
        {
            public void
            run()
            {
                try
                {
                    theSocket.close();
                }
                catch (IOException anException)
                {
                    System.out.println("assert!, closing a running " +
                        "acceptor should not cause problems");
                }
            }
        };
        
        theAcceptingThread.start();
        
        synchronized (this)
        {
            try
            {
                wait(5000); // wait 5 secs
            }
            catch (Exception anException)
            {
                // empty
            }
        }
        
        theClosingThread.start();
    }
    
    //--------------------------------------------------------------------
    public static void
    main(String[] anArgList)
    {
        Bug myBug = new Bug();
    }
    
    //--------------------------------------------------------------------
    // members
    //--------------------------------------------------------------------
    private ServerSocket theSocket;
    private Thread theAcceptingThread;
    private Thread theClosingThread;
}
(Review ID: 109055)
======================================================================