swing-awt-frame

Frame

maximize
frame.setExtendedState(JFrame.MAXIMIZED_BOTH);

Bring to Front
frame.setAlwaysOnTop(true);
frame.setAlwaysOnTop(false);

Request focus
frame.requestFocus();

Sizing,Visibility

frame.pack();
frame.setVisible(true);
frame.setExtendedState(JFrame.MAXIMIZED_BOTH);

Get Screen size

Toolkit kit = Toolkit.getDefaultToolkit();
Dimension screenSize = kit.getScreenSize();