Java Swing : Create Frame with Screen Size Dimension

JFrame frame=new JFrame();
frame.setSize((int)Toolkit.getDefaultToolkit().getScreenSize().getWidth(), (int)Toolkit.getDefaultToolkit().getScreenSize().getHeight());

http://stackoverflow.com/questions/6777135/java-jframe-size-according-to-screen-resolution

Another alternative is to use:

JFrame frame=new JFrame();
frame.setExtendedState(JFrame.MAXIMIZED_BOTH);