Null Pointer Exception after checking with 'if' statement

Question

I\'m getting a really annoying error, saying I\'m getting a null pointer exception but there\'s an if statement to check to see if the text is null before proceeding:

<

Answer 1

My guess is either textToAdd or RF is null.

If textToAdd is a JTextComponent (or subclass, but I'm guessing here), then its getText() method CANNOT return null. Therefore, Text CANNOT be null, as this test shows.

package test;

import javax.swing.JFrame;
import javax.swing.JTextField;

public class TextComponentTest extends JFrame {
    JTextField tf;

    public TextComponentTest() {
        super();
        tf = new JTextField();
        getContentPane().add(tf);
    }

    public static void main(String[] args) {
        TextComponentTest test = new TextComponentTest();
        test.setVisible(true);

        String s = test.tf.getText();
        System.out.println(">" + s + "<");
        System.out.println(">" + s.length() + "<");

        test.tf.setText(null);
        s = test.tf.getText();
        System.out.println(">" + s + "<");
        System.out.println(">" + s.length() + "<");
    }
}

Output is:

><
>0<
><
>0<

Answer 2

 if(Text.equals(null));

The above will throw a NullPointerException each time Text is null. Anytime you use the "." operator on null you get a NullPointerException.

If you are getting a NPE after if(Text != null), please post the stack trace.