Java tutorial
import java.awt.Dimension; import javax.swing.JFrame; import javax.swing.JPanel; public class Main extends JPanel { private static final int PREF_W = 400; private static final int PREF_H = 300; @Override public Dimension getPreferredSize() { return new Dimension(PREF_W, PREF_H); } private static void createAndShowGui() { Main myPanel = new Main(); JFrame frame = new JFrame(); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); frame.getContentPane().add(myPanel); frame.setResizable(false); frame.pack(); frame.setVisible(true); } public static void main(String[] args) { createAndShowGui(); } }