import java.util.*;
import java.util.zip.*;
import java.util.List;
import java.util.regex.*;
import java.util.concurrent.*;
import java.util.concurrent.atomic.*;
import java.util.concurrent.locks.*;
import javax.swing.*;
import javax.swing.event.*;
import javax.swing.text.*;
import javax.swing.table.*;
import java.io.*;
import java.net.*;
import java.lang.reflect.*;
import java.lang.ref.*;
import java.lang.management.*;
import java.security.*;
import java.security.spec.*;
import java.awt.*;
import java.awt.event.*;
import java.awt.image.*;
import javax.imageio.*;
import java.math.*;
import static java.awt.GraphicsDevice.WindowTranslucency.*;
public class main {


 
static class GradientTranslucentWindowDemo extends JFrame {
    public GradientTranslucentWindowDemo() {
        super("GradientTranslucentWindow");
 
        setBackground(new Color(0,0,0,0));
        setSize(new Dimension(300,200));
        setLocationRelativeTo(null);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
 
        JPanel panel = new JPanel() {
            @Override
            protected void paintComponent(Graphics g) {
                if (g instanceof Graphics2D) {
                    final int R = 240;
                    final int G = 240;
                    final int B = 240;
 
                    Paint p =
                        new GradientPaint(0.0f, 0.0f, new Color(R, G, B, 0),
                            0.0f, getHeight(), new Color(R, G, B, 255), true);
                    Graphics2D g2d = (Graphics2D)g;
                    g2d.setPaint(p);
                    g2d.fillRect(0, 0, getWidth(), getHeight());
                }
            }
        };
        setContentPane(panel);
        setLayout(new GridBagLayout());
        add(new JButton("I am a Button"));
    }
}

public static void main(final String[] args) throws Exception {
  // Determine what the GraphicsDevice can support.
  GraphicsEnvironment ge = 
      GraphicsEnvironment.getLocalGraphicsEnvironment();
  GraphicsDevice gd = ge.getDefaultScreenDevice();
  boolean isPerPixelTranslucencySupported = 
      gd.isWindowTranslucencySupported(PERPIXEL_TRANSLUCENT);

  //If translucent windows aren't supported, exit.
  if (!isPerPixelTranslucencySupported) {
      System.out.println(
          "Per-pixel translucency is not supported");
          System.exit(0);
  }

  JFrame.setDefaultLookAndFeelDecorated(true);

  // Create the GUI on the event-dispatching thread
  SwingUtilities.invokeLater(new Runnable() {
      @Override
      public void run() {
          GradientTranslucentWindowDemo gtw = new GradientTranslucentWindowDemo();

          // Display the window.
          gtw.setVisible(true);
      }
  });
}

static void setContentPane(JFrame frame, Container c) {
  frame.setContentPane(c);
  revalidate(frame);
}


static void revalidate(Component c) {
  if (c == null || !c.isShowing()) return;
  // magic combo to actually relayout and repaint
  c.revalidate();
  c.repaint();
}

}