import javax.swing.JFrame;
JFrame frame = new JFrame(); // creates jframe, sets it as "frame"
frame.setVisible(true) // Visibility boolean value, true or false, to hide the JFrame, set it to false

class class123{
public static void main(String[] args){ Jframe name-of-frmae =new Jframe; frame.setsize(x,y); frame.setdefaultcloseoperation(jframe.exit_on_close); frame.setvisble(true);
}
}