Question

I am trying to build a java microblogging app
I have finished the code but cannot connect to my own computer due to the following error (I google it and someone said I need to change the port number. I changed the port number and nothing happened)

Exception in thread "Thread-4" java.net.BindException: Address already in use: JVM_Bind

Below is the code for the server:

public class server extends Thread {
    public Socket client = null;
    public ServerSocket server = null;
    private int port = 4444; 

public void run(){  
    while (true){ //loop waits for incomming connection
        try { //start the server and listen to a port
                server = new ServerSocket(port);
            }catch (IOException e){
                System.err.println(e);
                System.exit(-1);
            }

            try { //establish a connection when receiving request
                client = server.accept();
            }catch (IOException e){
                System.err.println(e);
                System.exit(1);
            }

            Thread t = new Thread(new Connection(client));
            t.start();
        }
    }
}

And this is the code to start the server and listen to port 4444

Server server = new Server();
server.start(); //to listen to a port

Thank you

Answer 1

You must create the ServerSocket before entering the loop. At present you are trying to create it every iteration, which doesn’t make sense, and you aren’t closing it, so the second creation fails.