Name: nt126004 Date: 09/19/2001


java version "1.3.1"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.3.1-b24)
Java HotSpot(TM) Client VM (build 1.3.1-b24, mixed mode)

This bug is only under Linux and only when the client and the server are on the
same computer (localhost).
I create a server socket and a client socket, the server socket only accept one
client and wait for a byte (socket.getInputStream().read()).
The client connect to the server, launch an other thread used to close the
socket after 3 seconds.After launching this thread, but before the
socket.close(), the client wait for a byte on the input stream of the socket.
Under Windows, when the client close his socket, the call to read on the server
side unblock, returing -1 and I can handle client disconnection.
But under Linux, even if the socket.close() success (log before and after the
call to socket.close()),the read on the client does not return and is still
blocked, I think because the socket is not really closed by the OS.
As a result, the server call to read does not return either, and the client
disconnection is not detected.

Here is the code sample of this bug ( 2 files ServerSocketTest.java and
ClientSocketTest.java)

/*************************ServerSocketTest.java*******************************/
import java.io.*;
import java.net.*;

public class ServerSocketTest {

  private static final int DEFAULT_PORT = 3000;

/**
 * Wait for a client connection, and then wait for a byte
 * from this client.
 */
  public ServerSocketTest() {
    try{
      ServerSocket srvSock = new ServerSocket(DEFAULT_PORT);
      Socket s = srvSock.accept();
      System.out.println("Client connected from " + s.getInetAddress());
      System.out.println("Start reading 1 byte");
      int read = s.getInputStream().read();
      if (read == -1) throw new IOException("EOF reached");
      System.out.println("Byte read ok");
    } catch (IOException ioe) {
      System.out.println("Client disconnected");
      ioe.printStackTrace();
    }
  }

  public static void main(String[] args) {
    new ServerSocketTest();
  }

}

/*************************ClientSocketTest.java*******************************/
import java.io.*;
import java.net.*;

public class ClientSocketTest {

  private static final int DEFAULT_PORT = 3000;

  /**
   * Class use to close the socket.
   * Wait 3 seconds in an other thread and close the Socket.
   */
  class SocketCloser implements Runnable {
    Socket s;
    public SocketCloser(Socket s){
      this.s = s;
    }

    public void run() {
      synchronized (this) {
        try{ this.wait(3000); } catch (InterruptedException ie) {
ie.printStackTrace(); }
      }
      System.out.println("Closing socket");
      try{ s.close(); } catch (IOException ioe) { ioe.printStackTrace(); }
      System.out.println("Socket closed");
    }
  }

  /**
   * Create the socket, start the SocketCloser thread and
   * wait for a byte on the input stream of the socket.
   */
  public ClientSocketTest(){
    try{
      Socket socket = new Socket("127.0.0.1",DEFAULT_PORT);
      (new Thread(new SocketCloser(socket))).start();
      System.out.println("Start reading 1 byte");
      int read = socket.getInputStream().read();
      if (read == -1) throw new IOException("EOF reached");
      System.out.println("Read byte ok");
    } catch (IOException ioe) {
      ioe.printStackTrace();
    }
  }

  public static void main(String[] args) {
    new ClientSocketTest();
  }
}

No trace and no Exception.
(Review ID: 132110)
======================================================================