Multiple client single server problem(it hangs halfway)

Question

TestThread Class
import java.io.*;
import java.net.*;
import java.awt.*;
import javax.swing.*;
import java.util.*;
import java.util.Timer;// for timer
import java.util.TimerTask;//for timer
public class TestThread {
  public static void main(String[] args) {
    DataInputStream inputFromClient1;
    DataOutputStream outputToClient1;
    DataInputStream inputFromClient2;
    DataOutputStream outputToClient2;
    ServerSocket serverSocket = null;
    System.out.println("MastermindServer started at " + new Date() + "\n");
    try {
      serverSocket = new ServerSocket(8000);
    } catch(IOException ex) {
      System.err.println(ex);
    try {
      Socket socket = serverSocket.accept();
      System.out.println("sc1 connected \n\n\n\n");
      inputFromClient1 = new DataInputStream(socket.getInputStream());
      outputToClient1 = new DataOutputStream(socket.getOutputStream());
      String startMessage = "Two players now,You can start multiGame!";
      outputToClient1.writeUTF(startMessage);
      outputToClient1.writeUTF("hehehe");
      outputToClient1.writeUTF("hahaha");
      Socket socket1 = serverSocket.accept();
      System.out.println("sc 2 connected \n\n\n\n");
      inputFromClient2 = new DataInputStream(socket1.getInputStream());
      outputToClient2 = new DataOutputStream(socket1.getOutputStream());
      outputToClient2.writeUTF(startMessage);
      outputToClient2.writeUTF("hehehe");
      outputToClient2.writeUTF("hahaha");
//problem starts here when both are not received
      System.out.println("Problem starts here");
      int y = new DataInputStream(socket.getInputStream()).readInt();
      System.out.println("message from client 1 : "+ y);
      int x = new DataInputStream(socket1.getInputStream()).readInt();
      System.out.println("message from client 2 : "+ x);
      outputToClient1.writeUTF("1  hehehe");
      outputToClient1.writeUTF("1  hahaha");
      outputToClient2.writeUTF("1  hehehe");
      outputToClient2.writeUTF("1  hahaha");
    } catch(IOException ex) {
      System.err.println(ex);
}testSocket class
import java.io.*;
import java.net.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.event.*;
import javax.swing.border.Border;//for borders
import javax.swing.border.LineBorder;//for border lines
import java.awt.event.ActionEvent;//for action event
import java.awt.event.ActionListener;//for action listener
import javax.swing.*;
import java.util.*;
import java.util.Timer;// for timer
import java.util.TimerTask;//for timer
public class testSocket {
  public static void main(String[] args) {
    new testSocket();
  public testSocket() {
       DataOutputStream outputToServer;
    DataInputStream inputFromServer;
    try {
      // Create a socket to connect to the server
      Socket socket = new Socket("localhost", 8000);
      inputFromServer = new DataInputStream(socket.getInputStream());
      outputToServer = new DataOutputStream(socket.getOutputStream());
      String message = inputFromServer.readUTF();
      System.out.println(message);//start mess
      message = inputFromServer.readUTF();
      System.out.println(message);//hehehe
      message = inputFromServer.readUTF();
      System.out.println(message);//hahaha
      message = inputFromServer.readUTF();
      new DataOutputStream(socket.getOutputStream()).writeInt(99);     
      System.out.println(message);
      message = inputFromServer.readUTF();
      System.out.println(message);
    } catch (IOException ex) {
      System.err.println(ex);
    System.out.println("connected liao");
}Problem description:-
I simplified this problem from my long code into 2 test files with the problem only.
TestThread.java is the server
testSocket.java is the client
Running TestThread.java first then run testSocket twice without closing any would only show that it executes till line 46 and refuses to run further
It would execute the TestThread till line 38 and not go further.
Any help with this problem? Say I delete line 38 of testSocket and line 49-52 of TestThread, it would work fine but wouldn't work with input from different clients which would result in the program to hang there. I need to have input and output from different clients to the server at different time and interchangeable from one client to the other. In my program, the clients does different jobs so use of threads is out of the question.

Answer 1

I found your mistake.
Your clients are trying to receive a message that server has not sent.
String message = inputFromServer.readUTF(); //read start message
System.out.println(message);//start mess
message = inputFromServer.readUTF(); //read hehehe message
System.out.println(message);//hehehe
message = inputFromServer.readUTF(); //read hahaha message
System.out.println(message);//hahaha
message = inputFromServer.readUTF(); //<<----- what message? hangs waiting a server message
new DataOutputStream(socket.getOutputStream()).writeInt(99);      //this is not executed
...And your server hangs wait your clients int.
Anyway, you should not recreate the DataOuputStream! use the objects you've already create.
Lines 49 to 52 on server should be:
int y = inputFromClient1.readInt();
System.out.println("message from client 1 : "+ y);
int x = inputFromClient2.readInt();
System.out.println("message from client 2 : "+ x);It also applies to your client, see line 40.
Regards,
Henrique Abreu