Java tutorial
import java.awt.Color; import javax.swing.JComboBox; import javax.swing.JComponent; import javax.swing.JFrame; import javax.swing.JPanel; import javax.swing.WindowConstants; public class Main { public static JComponent makeUI() { JPanel p = new JPanel(); p.setBackground(new Color(.5f, .5f, .5f, .5f)); p.add(new JComboBox<String>(new String[] { "aaa", "bb", "c" })); JComboBox c = new JComboBox<String>(new String[] { "aaa", "bb", "c" }); p.add(c); return p; } public static void main(String[] args) { JFrame.setDefaultLookAndFeelDecorated(true); JFrame f = new JFrame(); f.setBackground(new Color(0, true)); // 1.7.0 f.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE); f.getContentPane().add(makeUI()); f.setSize(320, 240); f.setLocationRelativeTo(null); f.setVisible(true); } }