title: Transparent JPanel
body: <p>I want to create a semi-transparent JPanel. I've done it by simply using RGBA value of color constructor but problem is when i m using event handling is not woking properly. My requirement is a semi transparent Jpanel when mouse enters it border of this panel became visible and if mouse exit the border shoud not visible. I have done this by following code but problem is its not working properly for transparent backgroud (RGBA) but it working fine for RGB color. </p>
  
  <pre><code>import javax.swing.*;
  import javax.swing.border.*;
  import java.awt.*;
  import java.awt.event.*;
  
  public class MDCW extends JFrame {
  
        private JPanel contentPane;
  
       /**
       * Launch the application.
       */
       public static void main(String[] args) {
          EventQueue.invokeLater(new Runnable() {
              public void run() {
                  try {
                      MDCW frame = new MDCW();
                      frame.setVisible(true);
                  } catch (Exception e) {
                      e.printStackTrace();
                  }
              }
          });
      }
  
      /**
       * Create the frame.
       */
      public MDCW() {
          setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
          setBounds(100, 100, 1013, 551);
          contentPane = new JPanel();
          contentPane.setBackground(new Color(0, 139, 139));
          contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));
          setContentPane(contentPane);
          contentPane.setLayout(null);
  
          final JPanel panel = new JPanel();
  
          panel.setBackground(new Color(0, 0, 0,50));
          panel.addMouseListener(new MouseAdapter() {
              @Override
              public void mouseEntered(MouseEvent e) {
                  panel.setBorder(new LineBorder(new Color(255, 255, 255), 5));   
              }
              @Override
              public void mouseExited(MouseEvent e) {
                  panel.setBorder(null);  
              }
          });
          panel.setBounds(360, 155, 215, 215);
          contentPane.add(panel);
  
          final JPanel panel_1 = new JPanel();
          panel_1.setBackground(new Color(0, 0, 0));
          panel_1.addMouseListener(new MouseAdapter() {
              @Override
              public void mouseEntered(MouseEvent e) {
                  panel_1.setBorder(new LineBorder(new Color(255, 255, 255), 5)); 
              }
              @Override
              public void mouseExited(MouseEvent e) {
                  panel_1.setBorder(null);    
              }
          });
          panel_1.setBounds(84, 155, 215, 215);
          contentPane.add(panel_1);
      }
  }
  </code></pre>