Name: nt126004 Date: 08/15/2001


java version "1.4.0-beta"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.4.0-beta-b65)
Java HotSpot(TM) Client VM (build 1.4.0-beta-b65, mixed mode)

If a serverSocket is created, then accept some connections from client side. If
the client sides close all the connections before serverSocket.close(),
everything is fine. But if the server side wants to close the serverSocket
without notifying the client, after closing all the connections, it will
produce some problem. Although no exeption is thrown, however, if the program
creates another serverSocket on the same port, errors about "Address already in
Used: JVM_Bind" will be thrown. Looks like the port has not been released by
the serverSocket.close() method. However, this bug only exists in JDK1.4, for
JDK1.3.0_02 or JDK1.2, it is no problem.

The SOURCE CODE is as follows: the server creates a serverSocket, accepts five
connections from client thread, closes each connection just after it is
created, then closes the serverSocket, waits for two seconds, then creates the
serverSocket again:

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

public class Testing {

private ServerSocket server;

   public Testing() {
TestingClient tc=new TestingClient();
      tc.start();
}

public void runServer() {
System.out.println("Server starting");
try {
server=new ServerSocket(4000);
System.out.println( "Server Socket successfully created!" );
for (int ii=0; ii<3; ii++) {
Socket connection = server.accept();
System.out.println("Server: new connection accepted remote port="+connection.getPort());
connection.close();
}
server.close();
Thread.sleep(2000);
server=new ServerSocket(4000);
System.out.println( "Server Socket successfully created again!" );
server.close();
} catch (Exception e) { e.printStackTrace(); }
}

public static void main (String[] ppppp) {
Testing testing=new Testing();
testing.runServer();
}

}


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

class TestingClient extends Thread {

Socket clientSocket;

public void run() {
try {
sleep(5000);
System.out.println("Client starting");

for (int ii=0; ii<3; ii++) {
clientSocket = new Socket(InetAddress.getByName("localhost"),4000);
System.out.println("Client: socket "+(ii+1)+"created "+clientSocket.getLocalPort());
}
} catch (Exception e) {e.printStackTrace();}

}
}


The trace information is as follows:

For JDK 1.4:

C:\temp>\jdk1.4\jre\bin\java Testing
Server starting
Server Socket successfully created!
Client starting
Server: new connection accepted remote port =1478
Client: socket 1 created 1478
Server: new connection accepted remote port =1479
Client: socket 2 created 1479
Server: new connection accepted remote port =1480
Client: socket 3 created 1480
java.net.BindException: Address already in use: JVM_Bind
        at java.net.PlainSocketImpl.socketBind(Native Method)
        at java.net.PlainSocketImpl.bind(PlainSocketImpl.java:310)
        at java.net.ServerSocket.bind(ServerSocket.java:305)
        at java.net.ServerSocket.bind(ServerSocket.java:265)
        at java.net.ServerSocket.<init>(ServerSocket.java:201)
        at java.net.ServerSocket.<init>(ServerSocket.java:102)
        at Testing.runServer(Testing.java:29)
        at Testing.main(Testing.java:40)

For JDK 1.3.0_02:

C:\temp>\jdk1.3.0_02\bin\java Testing
BackupServer constructor
Server starting
Server Socket successfully created!
Client starting
Server: new connection accepted remote port =1466
Client: socket 1 created 1466
Server: new connection accepted remote port =1467
Client: socket 2 created 1467
Client: socket 3 created 1468
Server: new connection accepted remote port =1468
Server Socket successfully created again!

Additional: if the client closes all the connections before the server call
serverSocket.close(), it will be fine.
(Review ID: 130040)
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