Name: dc32491 Date: 03/28/2001


Any 1.2.2 or 1.3 JDK on Win 2000

C:\temp\ex1>java -version
java version "1.2.2"
Classic VM (build JDK-1.2.2_005, native threads, symcjit)


If thread T1 is blocked at a DatagramThread.receive() and thread T2 sends data
on the same socket, the receive throws java.net.SocketException if the
SecurityManager is installed. Things work fine when there is no security manager
is installed.

Steps to reproduce:
prompt> java -Djava.security.manager Server

You will see that all attempts to receive will now throw a
java.net.SocketException.

On Solaris the behavior seems correct and send() throws access denied exception.

The source code to reproduce the problem is below. Borland VisiBroker's OSAGENT
completely depends on the correct behavior and the incorrcet behavior is
resulting in a CPU load increasing to 100% on win 2000 systems.

import java.net.*;
import java.io.*;
 
public class Server {
 
  static int receive_on_port = 20000;
  static int send_to_port = 23000;
 
  public static void main(String[] args) {
    System.out.println("SecurityManager = " + System.getSecurityManager());
 
    try {
      DatagramSocket ds = new DatagramSocket(receive_on_port);
      new ReceiveThread(ds);
 
      Thread.currentThread().sleep(5000);
      System.out.println("Sending some data on the same socket...");
      // Send some data on the same socket
      byte[] data = new byte[] { 65 };
      DatagramPacket packet =
        new DatagramPacket(data, data.length,
                           InetAddress.getByName("localhost"), send_to_port);
      ds.send(packet);
    } catch (Exception e) {
      e.printStackTrace();
    }
  }
}
 
 
class ReceiveThread extends Thread {
  DatagramSocket ds;
  byte[] buffer = new byte[4096];
 
  public ReceiveThread(DatagramSocket ds) {
    this.ds = ds;
    start();
  }
 
 
  public void run() {
    DatagramPacket dp = new DatagramPacket(buffer, buffer.length);
    while (true) {
      try {
        System.out.println("Attempting to recive data on " + ds.getLocalPort());
        ds.receive(dp);
        String s = new String(dp.getData(), 0, 0, dp.getLength());
        System.out.println(dp.getAddress() + " at port " + dp.getPort() + " says " + s);
      }
      catch (IOException e) {
        System.err.println(e);
      }
} // end while
  }
}
(Review ID: 119611)
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