How to resize jframe to screen resolution in netbeans?

frame.setExtendedState(JFrame.MAXIMIZED_BOTH);
frame.setVisible(true);
// If you want to always keep the frame at this size
frame.setResizable(false);

Here is a very simple example, it might be a good start for your application:

import javax.swing.JFrame;

public class MyFrame
{
    private JFrame frame;

    public MyFrame()
    {
        frame = new JFrame();

        frame.setExtendedState(JFrame.MAXIMIZED_BOTH);
        frame.setVisible(true);
        frame.setResizable(false);
    }
    public static void main(String[] args)
    {
        new MyFrame();
    }
}