title: MouseListener methods overridden but compiler says otherwise?
body: <pre><code>        JTextArea messageDisplayArea=new JTextArea();
          messageDisplayArea.addMouseListener(new MouseListener(){
              public void mouseEntered(MouseEvent m){
                  JOptionPane.showMessageDialog(null,"a");
              }
          });
          messageDisplayArea.addMouseListener(new MouseListener(){
              public void mouseExited(MouseEvent m){
  
              }
          });
          messageDisplayArea.addMouseListener(new MouseListener(){
              public void mouseClicked(MouseEvent m){
  
              }
          });
          messageDisplayArea.addMouseListener(new MouseListener(){
              public void mousePressed(MouseEvent m){
  
              }
          });
          messageDisplayArea.addMouseListener(new MouseListener(){
              public void mouseReleased(MouseEvent m){
  
              }
          });
  </code></pre>
  
  <p>This is part of my code, I've imported java.awt.* and java.awt.event.* and javax.swing.* but have NOT implemented the MouseListener interface. I've overridden all the methods from the MouseListener interface but the compiler throws 5 errors, all saying that class is not abstract and does not override abstract method in MouseListener. What am I doing wrong?</p>