最新的jdk-6u10版本已经在进行beta测试，对于swing来说，在此版本中增加了两个重要的功能：透明窗体和不规则窗体。这两个功能使得swing也可以做出vista下的玻璃效果来了，
jdk-6u10还没有正式发布，可以在http://download.java.net/jdk6/binaries/进行下载
透明窗体：

public class TranslucentWindow extends JFrame {
    public TranslucentWindow() {
        super("透明窗体");
        this.setLayout(new FlowLayout());
        this.add(new JButton("按钮"));
        this.add(new JCheckBox("复选按钮"));
        this.add(new JRadioButton("单选按钮"));
        this.add(new JProgressBar(20, 100));
        this.setSize(new Dimension(400, 300));
        this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    }

    public static void main(String[] args) {
        JFrame.setDefaultLookAndFeelDecorated(true);
        SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                Window w = new TranslucentWindow();
                w.setVisible(true);
                com.sun.awt.AWTUtilities.setWindowOpacity(w, 0.6f);
            }
        });
    }

}

不规则窗体：
 

public class ShapedWindow extends JFrame {
    public ShapedWindow() {
        super("不规则窗体");
        this.setLayout(new FlowLayout());
        this.add(new JButton("按钮"));
        this.add(new JCheckBox("复选按钮"));
        this.add(new JRadioButton("单选按钮"));
        this.add(new JProgressBar(0, 100));

        this.setSize(new Dimension(400, 400));
        this.setLocationRelativeTo(null);
        this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    }

    public static void main(String[] args) {
        JFrame.setDefaultLookAndFeelDecorated(true);
        SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                Window w = new ShapedWindow();
                w.setVisible(true);
                com.sun.awt.AWTUtilities.setWindowShape(w, new Ellipse2D.Double(0, 0, w.getWidth(), w.getHeight()));
                com.sun.awt.AWTUtilities.setWindowOpacity(w, 0.93f);
            }
        });
    }

}

TAG:
Swing