.swing">setContentPane</a>, <a href="https://docs.oracle.com/javase/8/docs/api/javax/swing/JFrame.html?is-external=true#setDefaultCloseOperation-int-" title="class or interface in javax.swing">setDefaultCloseOperation</a>, <a href="https://docs.oracle.com/javase/8/docs/api/javax/swing/JFrame.html?is-external=true#setDefaultLookAndFeelDecorated-boolean-" title="class or interface in javax.swing">setDefaultLookAndFeelDecorated</a>, <a href="https://docs.oracle.com/javase/8/docs/api/javax/swing/JFrame.html?is-