//Center frame
Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();
Dimension size = frame.getSize();
screenSize.height = screenSize.height/2;
screenSize.width = screenSize.width/2;
size.height = size.height/2;
size.width = size.width/2;
int y = screenSize.height - size.height;
int x = screenSize.width - size.width;
frame.setLocation(x, y);