How to change font in Java gui application?

You can start by listing the available font names using something like ...

String fonts[]
        = GraphicsEnvironment.getLocalGraphicsEnvironment().getAvailableFontFamilyNames();

for (int i = 0; i < fonts.length; i++) {
    System.out.println(fonts[i]);
}

      

        
        
        
      

    

This is a great way to check font names.

If you do this, you will find that "Comic Sans" is listed as "Comic Sans MS", which means you need to use something like new Font("Comic Sans MS", Font.PLAIN, 24)

to create a new font

For example...

Shown: Comic Sans MS, Calibri, Default and Default

public class TestPane extends JPanel {

    public TestPane() {
        setLayout(new GridBagLayout());
        JLabel label = new JLabel("Hello");
        label.setFont(new Font("Comic Sans MS", Font.PLAIN, 24));
        GridBagConstraints gbc = new GridBagConstraints();
        gbc.gridwidth = GridBagConstraints.REMAINDER;
        add(label, gbc);

        label = new JLabel("Hello");
        label.setFont(new Font("Calibri", Font.PLAIN, 24));
        add(label, gbc);

        label = new JLabel("Hello");
        Font font = label.getFont();
        label.setFont(font.deriveFont(Font.PLAIN, 24f));
        add(label, gbc);
    }

    @Override
    public Dimension getPreferredSize() {
        return new Dimension(200, 200);
    }

}