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Button class in java

                          button class

                                             Button class:
This class is used to create the command button, which is used to initiate the particular action.
The constructors of the Button class:
a)   Button()
b)   Button(String s)
Button() : This constructor is used to create the command button with not caption on it( caption is the information which is displayed over the command button)
Button(String s): This constructor is used to create the command button with s as a caption on it.
Methods:
1. setLabel()This method is used to set the information which we want to display over the command button i.e. its caption  
The general form of the method is ,  
void setLabel(String s)
 where ,    s is the information
2. getLabel()This method is used to return the string which is assigned as the caption of the Button
 The general form is,
  String getLabel()




Event Handling: Events are the action performed by the user or the system. Example of events:
a)   Clicking on the command button
b)   Clicking on the list box
c)   Double clicking on the items etc….
The package java.awt.event.* provides the various interfaces for handling the events.
The Button class objects generates the ActionEvent.For handling this event the java.awt.event package provides the ActionListener interface.

PROGRAM-4
import java.applet.*;
import java.awt.*;
import java.awt.event.*;
/*
<applet code="ButtonDemo1" height=200 width=200>
</applet>
*/
public class ButtonDemo1 extends Applet implements ActionListener
{
            Label l;
            public void init()
            {
                        l=new Label("                               ");
                        add(l);
                        Button b=new Button("Show");
                        add(b);
                        b.addActionListener(this);
            }
public void actionPerformed(ActionEvent ae)
            {
                        l.setText("Welcome To AWT");
            }
}

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