Answer:

ButtonFrame implements the ActionListener interface, so it must define each method described in the interface.

Implementing an Interface

For the ActionListener interface, there is only one method: actionPerformed(). Here is the program with several blanks:

class ButtonFrame extends JFrame implements 
{
  JButton bChange ;

  // constructor   
  public ButtonFrame() 
  {
    bChange = new JButton("Click Me!"); 
    getContentPane().setLayout( new FlowLayout() );  
    getContentPane().( bChange ); 
    setDefaultCloseOperation( WindowConstants.EXIT_ON_CLOSE );    
  }
   
  // listener method required by the interface
  public void ( ActionEvent evt)
  {
     . . . . . .
  }
}

Answer:

Implementing an Interface

QUESTION 13: