accessing a textfield

[turkmen38]

hi every one
i am new to java and object oriented programming.my problem is that i wanna acces a text field...in a frame i created a text area and a button.i want to populate textarea when the button is clicked..i know it is very simple to you but i have been struggling with this for hours.....below is the source code...
thanx in advance

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/*
* i am trying to populate a textfield or textarea when a button is clicked...
*/
import java.awt.*;
import java.awt.event.*;
import java.awt.Button;
public class ForTestPurposesOnly extends GUIFrame
implements TextListener,ActionListener{
String msg=new String(" ");
int flag =0;
public ForTestPurposesOnly(){
super("Buttons And Text components together");
Button button=new Button("Click me!!!!");
button.addActionListener(this);
add(button,BorderLayout.SOUTH);
setSize(100,100);
setVisible(true);
TextField tf=new TextField();
tf.addTextListener(this);
add(tf,BorderLayout.NORTH);
pack();



}

public void actionPerformed(ActionEvent event){
if (event.getSource() instanceof Button){
System.out.println();

if (flag==0){
flag=1;
}
else{
flag=0;

}

}
}




public void textValueChanged(TextEvent event){
TextComponent src=(TextComponent)event.getSource();
if(flag==1){
src.setText("murtaza");
}
else{
src.setText("");
}

}







public static void main(String args[]){
new ForTestPurposesOnly();
}




}