I can't seem to find a function to check to see if a connection was success

Question

Hello everyone. I'm running into 2 problems that I can't seem to find functions for after reading the java API on socket and serverSocket.
If a client closed a connection on my server, like if someone telnets into my server, then closes the console, i get the following:
Event from: localhost-> null
Exception in thread "Thread-1" java.lang.NullPointerException
     at server.MultiThreadServer.run(MultiThreadServer.java:62)
     at java.lang.Thread.run(Thread.java:803)This is the check i do to avoid getting this, but it doesn't seem to work:
//close a connection on this condition.
              if(csocket.getRemoteSocketAddress() == null || input.equals("bye"))
                   System.out.println("Connection closed by client.");
                   break;
              }If I attempt to run a server socket on a socket that is already being used, I'd like to print out a statement saying its being used and do something about it, like let the user enter another port number. Right now I have:
public class MainTest {
       public static void main(String args[]) throws Exception
            //get console input
            BufferedReader stdin = new BufferedReader(new InputStreamReader(System.in));  
            System.out.println("Enter port to run server on: ");
            String input = stdin.readLine();
            int servPort = Integer.parseInt(input);
            try
            ServerSocket ssock = new ServerSocket(servPort);
            System.out.println("Listening on : " + ssock);
              while (true) {
                //waiting for client to connect to server socket
                Socket sock = ssock.accept();
                System.out.println(sock + " connected.");
                //get host information
                InetAddress clientIa = sock.getInetAddress( );
                String clientName = clientIa.getHostName();
                String clientIp = clientIa.getHostAddress();
                int localPort = sock.getLocalPort();
                System.out.println("hostname: "+clientName  +
                          '\n' + "Ip address: " + clientIp
                          +":"+ localPort + "\n\n");
                new Thread(new MultiThreadServer(sock)).start();
            catch(IOException e)
                 e.printStackTrace();
}Me catching the IOException is too broad....if anything goes wrong it will spit out the error and stop program execution as it should.
I tried
if(ssock.isClosed()) { System.out.println("Socket is being used, try another");but it doesn't work.
Also inside my server program I'm connecting to another server and if that other server isn't running I'd like to print out an error message stating that.
Right now it will just say: Connection Refused if its not running.
here's that code:
public class MultiThreadServer implements Runnable {
     Socket csocket;
  MultiThreadServer(Socket csocket) {
    this.csocket = csocket;
  public void run() {
    try {
      //setting up channel to recieve events from the omnibus server
         BufferedReader in= new BufferedReader(
                    new InputStreamReader(
                    csocket.getInputStream()));
         //This socket will be used to communicate with the reciever
         //we will need a new socket each time because this is a multi-threaded
         //server thus, the (outputServ) will need to be
         //multi threaded to handle all the output.
         Socket outputServ = new Socket("localhost",1234);
         if(outputServ.getLocalSocketAddress() == null)
              System.out.println("OutputServer isn't running...");
         //Setting up channel to send data to outputserv
          PrintWriter out
               = new PrintWriter(
               new OutputStreamWriter(
               outputServ.getOutputStream()));
         while(true)
              //accepting events from omnibus server and storing them
              //in a string for later processing.
              String input = in.readLine();
              //accepting and printing out events from omnibus server
              //also printing out connected client information
              System.out.println("Event from: " + csocket.getInetAddress().getHostName()
                        +"-> "+ input +"\n");
              out.println(input);
              out.flush();
              //close a connection on this condition.
              if(csocket.getRemoteSocketAddress() == null || input.equals("bye"))
                   System.out.println("Connection closed by client.");
                   break;
         //cleaning up
      in.close();
      out.close();
      outputServ.close();
      csocket.close();
    } catch (IOException e) {
      System.out.println(e);
      e.printStackTrace();
}Both those conditions don't seem to work, if a client closes a connection it doesn't respond and if the server isn't running on port 1234, i get that connection refused.
Any help would be great!

Answer 1

Thanks for the help guys!
adding -1 to the stream worked perfect:
i have it like this:
     String input;
     //accepting events from omnibus server and storing them
     //in a string for later processing.
     while ((input = in.readLine()) != null)  
              //accepting and printing out events from omnibus server
              //also printing out connected client information
              System.out.println("Event from: " + csocket.getInetAddress().getHostName()
                        +"-> "+ input +"\n");
              out.flush();
              out.println(input);
              out.flush();
              //close a connection on this condition.
              if(in.read() == -1)
                   System.out.println("Connection closed by client.");
                   break;
    //cleaning up
      in.close();
      out.close();
      outputServ.close();
      csocket.close();
    } I had one last question, when I catch a socketExpection, such as, if the user enters a port that is already in use, I would like to give them the chance to enter another port before stopping the program.
I'm not sure how I can do this with exceptions though, like i have:
  //setting up sockets
            ServerSocket ssock = null;
            Socket sock = null;
            try
            //setting up server to run on servPort
           ssock = new ServerSocket(servPort);
       catch (SocketException e )
                 System.out.println ("Socket error: " + e);
            }now inside that catch block, is there a way for me to allow the user to enter another socket and try again? or am I approaching this wrong?
while(true)
if the port is already been used
allow the user to enter in another port number
else
break;
}I'm confused on how this will work though becuase:
once it hits this line:
ssock = new ServerSocket(servPort);the exception is thrown and it jumps down to the catch block,
now inside that catch block how would I let the user enter in another port number and try this line of code again?
ssock = new ServerSocket(servPort); //this time with the new servPort number?
Thanks!