Question

Why is this program not working? (It doesn’t print “Running…”)

package eu.inmensia.learn;

import java.awt.Canvas;
import java.awt.Dimension;

import javax.swing.JFrame;

public class Client extends Canvas implements Runnable {

    private static final long serialVersionUID = 1L;
    public static final int WIDTH = 300;
    public static final int HEIGHT = WIDTH / 16 * 9;
    public static final short SCALE = 3;

    private Thread thread;
    private JFrame frame = new JFrame();
    private boolean running = false;

    public Client() {
        Dimension size = new Dimension(WIDTH * SCALE, HEIGHT * SCALE);
        setPreferredSize(size);
    }

    public synchronized void start() {
        running = true;
        thread = new Thread("display");
        thread.start(); // start the thread
    }

    public synchronized void stop() {
        running = false;
        try{
            thread.join(); // end the thread
        }catch(InterruptedException e){ e.printStackTrace(); }
    }

    public void run() {
        while(running){
            System.out.println("Running...");
        }
    }

    public static void main(String[] args) {
        Client client = new Client();
        client.frame.setResizeable(false);
        client.frame.setTitle("Program test");
        client.frame.add(client);
        client.frame.pack();
        client.frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        client.frame.setLocationRelativeTo(null);
        client.frame.setVisible(true);

        client.start();
    }
}

I’m trying to learn threads, and it’s one, if not the most hard, thing I ever have learned. OOP is nothing to this xD

Answer 1

Because of this

new Thread("display");

Change it to

new Thread(this)

I just hope you know what you’re doing.