Mi a problema a lenti java programmal? A button1-et miert az elso sorba kozepre helyezi?

import javax.swing.*;

public class Main

{

public static void main(String[] args)

{

JFrame window=new JFrame("My Frame");

window.pack();

window.setVisible(true);

window.setSize(800,700);

window.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

JPanel p=new JPanel();

JButton button1=new JButton("Button1");

button1.setBounds(20,30,70,60);

p.add(button1);

window.add(p);

}

}

button.setBounds(x,y,w,h);

az x,y a koordinata a w,h meg a button merete

A button1-et miert az elso sorba kozepre helyezi? Mi lehet a problema?