What is wrong using this keyword in Swing?

Question

I am asking this question due to mKorbel's second comment on this question . I have been using this keyword to call local variables, local components of that class (example Buttons) and methods etc I am not sure what is wrong with using the keyword the way I have been doing it.

don't to use this.whatever in Swing, Java, (in MCV make me some sence), use local variables insted of.

Question: What is wrong with using this.XXX in Swing?

Sample Code

public class SwingTest extends JFrame {

// variables
private String st = "You clicked me";

SwingTest() {
    this.initUI();

}

private void initUI() {
    this.setTitle("Swing Test");
    this.setSize(200, 200);
    this.setLayout(new BorderLayout());
    this.setVisible(true);

    this.clickMe = new JButton("Click"); // What is wrong with using this
                                            // ref here?

    this.add(clickMe);

    this.clickMe.addActionListener((ActionEvent) -> {
        JOptionPane.showMessageDialog(this, this.st);// What is wrong with
                                                        // using this ref
                                                        // here?
        });
}

public static void main(String[] args) {
    SwingUtilities.invokeLater(new Runnable() {

        @Override
        public void run() {
            SwingTest swingTest = new SwingTest();
        }
    });
}

// components
JButton clickMe;
}

Answer 1

The button clickMe does not need to be a field. It can be a local variable JButton clickMe inside the dialog defining method/constructor. As normally many GUI components are created and added to the window, it cleans up the class, keeps declarations close to usage, and leaves the life-time as short as possible (on changing window contents).

(The talk about this is merely to point out the fieldness of clickMe .)