How to close a GUI when i push a JButton

Question

Does anyone know how to make a jbutton close a gui? I think it is like System.CLOSE(0); but that didnt work. it also could be exitActionPerformed(evt);

Answer 1

JButton close = new JButton("Close");
close.addActionListener(this);
public void actionPerformed(ActionEvent closing) { 
// getSource() checks for the source of clicked Button , compares with the name of button in which here is close .     
if(closing.getSource()==close)
   System.exit(0);
   // This exit Your GUI 
}
/*Some Answers were asking for @override which is overriding the method the super class or the parent class and creating different objects and etc which makes the answer too long . Note : we just need to import java.awt.*; and java.swing.*; and Adding this command : class className implements actionListener{} */