Rewrite the following code to use a Lambda expression for the button action listener.

Question

What will be an ideal response?

Answer 1

Rewrite the following code to use a Lambda expression for the button action listener.
```
import java.util.ArrayList;
import javax.swing.JButton;
import javax.swing.JFrame;
import java.awt.Color;
import java.awt.Container;
import java.awt.FlowLayout;

public class ButtonDemo3 extends JFrame
{
public ButtonDemo3( )
{
setSize(250, 100);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setTitle("Button Demo");
Container contentPane = getContentPane( );
contentPane.setBackground(Color.BLUE);
contentPane.setLayout(new FlowLayout( ));

JButton goButton = new JButton("Green");
goButton.addActionListener(
{ e } -> contentPane.setBackground(Color.GREEN));
contentPane.add(goButton);
}

public static void main(String[] args)
{
ButtonDemo3 buttonGui = new ButtonDemo3( );
buttonGui.setVisible(true);
}
}

Answer:

import java.util.ArrayList;
import javax.swing.JButton;
import javax.swing.JFrame;
import java.awt.Color;
import java.awt.Container;
import java.awt.FlowLayout;

public class ButtonDemo3 extends JFrame
{
public ButtonDemo3( )
{
setSize(250, 100);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setTitle("Button Demo");
Container contentPane = getContentPane( );
contentPane.setBackground(Color.BLUE);
contentPane.setLayout(new FlowLayout( ));

JButton goButton = new JButton("Green");
goButton.addActionListener(
e -> contentPane.setBackground(Color.GREEN));
contentPane.add(goButton);
}

public static void main(String[] args)
{
ButtonDemo3 buttonGui = new ButtonDemo3( );
buttonGui.setVisible(true);
}
}
```