import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.SwingUtilities;
public class SimpleExample extends JFrame {
public SimpleExample() {
Your frame is under the control of a layout manager, it is making the decisions on how best to layout your components and is overriding the values you have specified using setBounds
Modern GUIs need to run (even on the same OS) in a variety of different graphical environments, including different DPI, screen sizes and font settings for example.
The layout manager makes it possible for you to worry (less) about these issues and it is highly recommended that you make use of them
Take a look at
For more details