Question

Using Input/Output stream to pass objects between my client and server. I can both send and receive objects with my server, and and now i want the same for the client which as of now only can send. So i gave my client an ObjectInputStream. However, when i initilazie it, it blocks! Been searching around and found answers but no solution.

Please help!

public GameConnection(String strPort, TextArea chat)
    {
        this.port = Integer.parseInt(strPort);
        System.out.println("GameConnection::Constructor(): Connecting on port " + port);
        this.chat = chat;


        connect = new Connection();
        sendObject();
    }
    public void sendObject()
    {
        try
        {  
            obj_stream.writeObject(new String("GameServer received a message!"));  
        }
        catch(Exception e){System.out.println("GameConnection::sendObject(): " + e);}  
    }  

    protected class Connection extends Thread
    {
        private boolean alive = true;

        public Connection()
        {
            try
            {
                socket = new Socket(host, port);
                System.out.println("Connected to GAMESERVER" + host + " on port + " + port);
                obj_stream = new ObjectOutputStream(socket.getOutputStream());
                // Next line BLOCKS!!!
                //ObjectInputStream stream = new ObjectInputStream(socket.getInputStream());
            }
            catch (IOException ioe)
            {
                System.out.println("Connection::constructor() " + ioe);
                Terminate();
            }
            catch (NullPointerException npe)
            {
                System.out.println("Connection::constructor() " + npe);;
                Terminate();
            }

        }

I tried using them in different threads but it had the same problem, at least for me 🙁

Answer 1

yes, this question has been asked many times before. the object stream format has a header, and the ObjectInputStream reads that header on construction. therefore, it is blocking until it receives that header over the socket. assuming your client/server code looks similar, after you construct the ObjectOutputStream, flush it. this will force the header data over the wire.