**"From Intermediate to Advanced Swing: Essential Tips for Leveling Up"**

1. Double Buffering: Your Animation Savior

That flickering during repaints? Gone. Implement custom double buffering for complex animations:

public class SmoothPanel extends JPanel {
    private BufferedImage buffer;
    
    @Override
    protected void paintComponent(Graphics g) {
        if(buffer == null || buffer.getWidth() != getWidth() 
                          || buffer.getHeight() != getHeight()) {
            buffer = new BufferedImage(getWidth(), getHeight(), 
                                     BufferedImage.TYPE_INT_ARGB);
        }
        
        Graphics bufferGraphics = buffer.getGraphics();
        super.paintComponent(bufferGraphics);
        // Your custom painting here
        
        g.drawImage(buffer, 0, 0, null);
        bufferGraphics.dispose();
    }
}

Pro tip: Combine with VolatileImage for hardware acceleration on supported systems.

2. SwingWorker: The Multithreading Lifeline

Blocking the EDT is amateur hour. Master SwingWorker for background tasks:

SwingWorker<ResultType, ProgressType> worker = new SwingWorker<>() {
    @Override
    protected ResultType doInBackground() throws Exception {
        // Long-running task
        publish(progressUpdate); // Intermediate updates
        return result;
    }
    
    @Override
    protected void process(List<ProgressType> chunks) {
        // Update UI with progress
    }
    
    @Override
    protected void done() {
        try {
            ResultType result = get();
            // Final UI update
        } catch (Exception e) {
            handleError(e);
        }
    }
};
worker.execute();

Bonus: Use PropertyChangeListener for state change notifications.

3. Custom Painting: Beyond Basic Components

When stock components won't cut it, roll your own with these advanced techniques:

• Shape Clipping: Create non-rectangular components
• AffineTransform: Rotate, scale, and skew graphics
• AlphaComposite: Master transparency effects

Example of a circular progress indicator:

@Override
protected void paintComponent(Graphics g) {
    Graphics2D g2d = (Graphics2D) g.create();
    g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING, 
                        RenderingHints.VALUE_ANTIALIAS_ON);
    
    // Background
    g2d.setColor(Color.LIGHT_GRAY);
    g2d.fillOval(5, 5, getWidth()-10, getHeight()-10);
    
    // Progress arc
    g2d.setStroke(new BasicStroke(8));
    g2d.setColor(Color.BLUE);
    g2d.drawArc(10, 10, getWidth()-20, getHeight()-20, 
               90, -(int)(360 * progress));
    
    g2d.dispose();
}

4. Look and Feel: Professional Polish

Elevate your UI from functional to phenomenal:

• Create custom UIDefaults overrides
• Design component-specific painters
• Implement Highlighter for text components

Modern flat LAF example:

UIManager.put("Button.arc", 20);
UIManager.put("Component.arc", 20);
UIManager.put("ProgressBar.arc", 20);
UIManager.put("TextComponent.arc", 5);

UIManager.setLookAndFeel(new FlatLightLaf());

Consider FlatLaf or MaterialUI for contemporary designs.

5. Performance Profiling: The Secret Weapon

Advanced Swing means knowing why it's slow:

• Use RepaintManager.setCurrentManager() to track repaints
• Profile with -Dswing.debug=graphics
• Monitor EDT with Toolkit.getDefaultToolkit().getSystemEventQueue().push()

Critical optimization checklist: