import java.awt.Dimension;
import java.awt.Toolkit;
import javax.swing.JFrame;
public class Main {
public static void main(String args[]) {
JFrame frame = new JFrame();
Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();
int width = (int) screenSize.getWidth();
int height = (int) screenSize.getHeight();
Dimension newDim = new Dimension(width, height - 40);
frame.setSize(newDim);
frame.setVisible(true); // FIRST visible = true
frame.setResizable(false); // THEN resizable = false
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
}