Java Network programming Interview Question:

Explain Look for Local Ports?

Submitted by: Administrator

Example 11-1: Look for Local Ports

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

public class LocalPortScanner {

public static void main(String[] args) {

for (int port = 1; port <= 65535; port++)
{

try {

// the next line will fail and drop into the
catch block if there is already a server
running on the port//

ServerSocket server = new ServerSocket(port);
}
catch (IOException e) {
System.out.println("There is a server on port
" + port + ".");
} // end try

} // end for

}

}

Here's the output I got when running
LocalPortScanner on my NT workstation:

D:JAVAJNP2examples11>java LocalPortScanner
There is a server on port 135.
There is a server on port 1025.
There is a server on port 1026.
There is a server on port 1027.
There is a server on port 1028.
Submitted by: Administrator