Question

public class Start {

public static void main(String[] args) {
    JFrame j = new JFrame();
    final Graphics g = j.getGraphics();
    JButton jb = new JButton("Start");
    j.add(jb);
    jb.addActionListener(new ActionListener() {

        @Override
        public void actionPerformed(ActionEvent arg0) {
            HeavenlyBiome.spread(g);

        }
    });

}

 }
 ...
 public class HeavenlyBiome {
static Random r = new Random();
public static void spread(Graphics g){
g.setColor(Color.yellow);
int spread = r.nextInt(2)+1;
if (spread==1){
    g.fillRect(0,600,10,10);
}

So I run this and everything compiles right with no errors but the problem is that no window appears! If it helps at all, this is all from a package that is not default, and maybe there’s something special you need to do when youre using a new package? I dont know because i’m a new coder so any help is appreciated!

Answer 1

Try calling setVisible(true) on your JFrame instance.

JFrame j = new JFrame();
JButton jb = new JButton("Start");
j.add(jb);

j.setVisible(true);

And read this: http://docs.oracle.com/javase/tutorial/uiswing/components/frame.html