How to replace in applet

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

/*


*/

public class replace extends Applet implements ActionListener
{
TextArea textarea1;
Button button1;

public void init()
{
textarea1 = new TextArea("Now is the time.", 5, 20,
TextArea.SCROLLBARS_BOTH);
add(textarea1);
button1 = new Button("Replace selected text");
add(button1);
button1.addActionListener(this);
}

public void actionPerformed (ActionEvent e){
if(e.getSource() == button1)
{
textarea1.replaceRange("Hello from Java!",
textarea1.getSelectionStart(),
textarea1.getSelectionEnd()) ;
}
}
}