Thread cannot read and write streams on the same socket at the same time?

Question

Code with lines commented-out works, code with those lines does not.....why? and how do I fix it? (note: roughly same code running on the other end)

    public void run() {
        try {
            ObjectOutputStream oos = new ObjectOutputStream(socket.getOutputStream);
            //ObjectInputStream ois = new ObjectInputStream(socket.getInputStream());
            while (true) {
                //System.out.println( ois.readUTF());
                oos.writeUTF("hey");
            }
        } catch (Exception e) {e.printStackTrace(); }
    }

Edit: Made some code to make it clearer what I'm getting at, yes its a little messy. (regardless of there being two sockets or not it doesn't seem to work):

Server.java (main):

public static void main(String[] args) {
    try {
        ServerSocket server = new ServerSocket(6666);
        ServerSocket server2 = new ServerSocket(6667);
        Socket socket = server.accept();
        Socket socket1 = server2.accept();
        OutputStream output = socket.getOutputStream();
        ObjectOutputStream oos = new ObjectOutputStream(output);
        ObjectInputStream ois = new ObjectInputStream(socket1.getInputStream());
        while (true) {
            System.out.println("server reading");
            System.out.println( ois.readUTF());
            System.out.println("server writing");
            oos.writeUTF("hey");
        }
    } catch (Exception e) {e.printStackTrace(); }
}

Client.java (main)

public static void main(String[] args) throws Exception {
    Socket socket = new Socket("127.0.0.1", 6666);
    Socket socket1 = new Socket("127.0.0.1", 6667);
    ObjectInputStream ois = new ObjectInputStream(socket.getInputStream());
    ObjectOutputStream oos = new ObjectOutputStream(socket1.getOutputStream());
    while (true) {
        System.out.println("client writing");
        oos.writeUTF("yo");
        System.out.println("client reading");
        System.out.println( ois.readUTF() );
    }
}

Output

Server:

server reading

Client:

client writing
client reading

Answer 1

.flush() your output streams. In my examples after writing on the output stream I have:

oos.flush();

I should have always flushed when I wanted to be sure the message was sent.