Extending JLabel in Java Swing to use a given font (super usage in extended classes)

Question

I am trying to create a new class JXLabel which inherits JLabel. Difference is that this extended class will assign a default font for the label.

If I try this:

public class JXLabel extends JLabel {

    Font f = new Font("Segoe UI", Font.PLAIN, 6);

    public JXLabel() {    
        super();
        this.setFont(f);
    }  

    public JXLabel(Icon icon) {
        super(icon);
        this.setFont(f);
    }  

    public JXLabel(Icon icon, int horizontalAlignment) {
        super(icon, horizontalAlignment);
        this.setFont(f);
    }  

    public JXLabel(String text) {
        super(text);
        this.setFont(f);
    }  

    public JXLabel(String text, Icon icon, int horizontalAlignment) {
        super(text, icon, horizontalAlignment);
        this.setFont(f);
    }  

    public JXLabel(String text, int horizontalAlignment) {
        super(text, horizontalAlignment);
        this.setFont(f);
    }  
}

I would expect new labels created as JXLabel to have this default font, but they do not.

If I create a regular JLabel and do:

myLabel.setFont(new Font("Segoe UI", Font.PLAIN, 6));

It works. Any tip on what is wrong in the extended class? Thanks.

Answer 1

Here is a MCVE of the above code, testing the assertion that one way it works, while the other it doesn't. Here, it works by either setting the font of a standard JLabel or by using a JXLabel.

See if you can:

1. Confirm the result on your machine
2. If it works as expected, track down the difference in the original code.

---

import java.awt.*;
import javax.swing.*;

public class JXLabelTest {

    public static void main(String[] args) {
        Runnable r = () -> {
            String s = "The quick brown fox jumps over the lazy dog";
            JLabel myLabel = new JLabel(s);
            myLabel.setFont(new Font("Segoe UI", Font.PLAIN, 6));
            JOptionPane.showMessageDialog(null, myLabel);
            JOptionPane.showMessageDialog(null, new JXLabel(s));
        };
        SwingUtilities.invokeLater(r);
    }
}

class JXLabel extends JLabel {

    Font f = new Font("Segoe UI", Font.PLAIN, 6);

    public JXLabel() {    
        super();
        this.setFont(f);
    }  

    public JXLabel(Icon icon) {
        super(icon);
        this.setFont(f);
    }  

    public JXLabel(Icon icon, int horizontalAlignment) {
        super(icon, horizontalAlignment);
        this.setFont(f);
    }  

    public JXLabel(String text) {
        super(text);
        this.setFont(f);
    }  

    public JXLabel(String text, Icon icon, int horizontalAlignment) {
        super(text, icon, horizontalAlignment);
        this.setFont(f);
    }  

    public JXLabel(String text, int horizontalAlignment) {
        super(text, horizontalAlignment);
        this.setFont(f);
    }  
}