Q6 weapons reward for answering Java question!!

Day 1,682, 07:38 Published in Brazil Romania by PuPazZ0
The Program

import java.applet.*;
import java.awt.*;
import java.awt.event.*;

public class MyApplet4 extends Applet implements ActionListener{
Button b = new Button("0");
int i;

public void init(){
add(b);
b.addActionListener(this);
}

public void actionPerformed(ActionEvent ev){
i++;
b.setLabel(i+"");
}

}


Question

If anyone can explain "b.setLabel(i+"");" --> reward 30 q6

Comment at article or PM with answers to frogs
Also the reward from him!