readLine() hangs in email app?!

[Dave Fribley]

Howdy Y'all! Java greenhorn here, with an email application readLine() hanging problem.

I'm just trying to build a simple POP3 client that downloads email headers from POP accounts. For some reason, my application will hang when trying to read the input stream after I have sent some text out the output stream. Here's the kicker, this code works flawlessly on another machine that I have tested it on. This problem appears to not pertain as much to the code.

Details: Using the latest JRE (1.4.2_04)

BufferedReader fromServer;
BufferedWriter toServer;
fromServer = new BufferedReader(new InputStreamReader(socket.getInputStream()));
toServer = new BufferedWriter(new OutputStreamWriter(socket.getOutputStream()));
 
// ..........
 
private void sendToServer(BufferedWriter out, String ostr) throws IOException {
 out.write(ostr + "\n");
 out.flush();
}
 
private String readFromServer(BufferedReader in) throws IOException {
 String rS;
 System.out.println(rS=in.readLine());
 return rS;
}
 
// ...........
 
public Email(String server,int port) {
    try {
      socket = new Socket(server,port);
      bConnected = true;
      fromServer = new BufferedReader(new InputStreamReader(socket.getInputStream()));
      toServer = new BufferedWriter(new OutputStreamWriter(socket.getOutputStream()));
      readFromServer(fromServer);
    }
    catch (UnknownHostException err) {System.out.println("Error: Unknown Host");}
    catch (IOException err) {System.out.println(err.toString());}
}
 
// .........
 
public boolean Authenticate(String uid,String pass) {
    if(!bConnected)
      return false;
    try {
      sendToServer(toServer,"USER " + uid);
      if(!ValidateResponse(readFromServer(fromServer))) throw new Exception("Invalid Username");
      sendToServer(toServer,"PASS " + pass);
      if(!ValidateResponse(readFromServer(fromServer))) throw new Exception("Invalid Password");
      return bLoggedIn = true;
    }
    catch (IOException err){}
    catch (Exception err) {System.out.println(err);}
    return false;
}
 
// ..........
 
private boolean ValidateResponse(String line) {
    if(line.startsWith("+OK")) return GOOD;
    return BAD;
}

Again, this code works just fine on one of my machines. I've been trying to isolate the differences in these machines, but I haven't found any that (I think) would affect this Java program. I've tried earlier JVMs and still have the same problem. Here's a sample output when the system hangs:

+OK (rwcrpxc55) Maillennium POP3/PROXY server #235
USER dfribley

**Program Hangs**

Here's a sample of the working machine:

+OK InterMail POP3 server ready.
USER dfribley
+OK please send PASS command
PASS *****
+OK dfribley is welcome here
STAT
+OK 0 0
QUIT
+OK dfribley InterMail POP3 server signing off.

Again, everything works great on another machine. Even though I'm using both of these computers on the same network configuration, I still have the hanging problem on one of them. When I try to run the app on other computers/network configs (friend's comps, etc.), the program hangs. I've also tried disabling Norton Anti-virus while running the application and it still hangs. A big difference my two machines is that the working one is using McAfee Enterprise 7, and the other is using Norton 2003.

Other than that, I have no idea why my application runs on one machine and not the other. Do I need to account for anything else in my code? What other factors are there when reading and writing to sockets with the JVM?

Thank you in advance for your help!!!

[ June 01, 2004: Message edited by: Dave Fribley ]
[ June 01, 2004: Message edited by: Dave Fribley ]

[Joe Ess]

1. Please don't crosspost
2. JavaMail is usually discussed in the Other API's forum, so I'm moving this post there.

[Dave Fribley]

UPDATE:

Well as it turns out, Norton was the one that was getting in the way of my application. When I disable Options->Mail->"Scan incoming mail" (In Norton 2003), my application works just fine.

Does anyone know details on why Norton email scanning is causing my application to hang after the first command? Is this also a problem for Norton 2004 users? Are there any adjustments that I can make in my code to account for Norton�s intervention?

Thanks for your help,