Using JButton - Minimize/Maximize/Close JFrame

You can use a JButton to perform the actions on the JFrame. This is also a tutorial for JButton with ActionListener.

Use JButton to Maximize/Minimize/Close JFrame

import javax.swing.*;
import java.awt.event.*;
import java.awt.*;
class JButtonWindowActions extends JFrame
{
JButton button1,button2,button3;
public JButtonWindowActions()
{
setTitle("JButtonWindowActions Demo");
setVisible(true);
setDefaultCloseOperation(EXIT_ON_CLOSE);
setLayout(new FlowLayout());
setOpacity(0.7f);
button1=new JButton("Maximize/Restore");
button1.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent ae)
{
if(getExtendedState()==NORMAL)
setExtendedState(MAXIMIZED_BOTH);
else
setExtendedState(NORMAL);
}
});
button2=new JButton("Minimize");
button2.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent ae)
{
setState(ICONIFIED);
}
});
button3=new JButton("Close");
button3.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent ae)
{
dispose();
}
});
// add buttons to frame
add(button1);
add(button2);
add(button3);
// pack the frame
pack();
}
public static void main(String args[])
{
new JButtonWindowActions();
}
}

setOpacity(0.7f): To just set the Opacity of the frame. It is optional.
NORMAL: Set the frame to the normal state i.e. it's original state.
MAXIMIZED_BOTH: Make the frame maximized i.e. spread it to the full screen.
ICONIFIED: Make the frame be at the task bar.
dispose(): Dispose the frame.