Help with running applet

Question

Hi all,
I have wrote this simple code which takes the input from two textboxes and then when the button is pressed, it adds the contents of the two boxes and displays them in the third textfield.
import java.awt.*;
import java.applet.*;
import java.awt.event.*;
public class Exercise extends Applet implements ActionListener
     private TextField inputA;
     private TextField inputB;
     private TextField output;
     private Button but1;
     public void init()
          inputA = new TextField(8);
          inputB = new TextField(8);
          but1 = new Button("Press To Add Values");
          add(but1);
          add(inputA);
          add(inputB);
          add(output);
          but1.addActionListener(this);
     public void actionPerformed(ActionEvent ae)
          int contentsOfA = Integer.parseInt(inputA.getText());
          int contentsOfB = Integer.parseInt(inputB.getText());
          int sum;
          if (ae.getSource()==but1)     
               sum = (contentsOfA + contentsOfB);
               output.setText(Integer.toString(sum));
}It compiles fine, but it wont execute when i try run it.
Also does anyone know where i can download the Microsoft Java VM?
Thanks for your help
Michael

Answer 1

It compiles fine, but it wont execute when i try run
it.What happens, then? Did you run it in appletviewer or your browser? Did you get an error message? If you run it in your browser, you should open the Java Console to view error messages.
It looks like you never initialize the output Textfield so I think you are getting a NullPointerException.