//...
final JPopupMenu popup = new JPopupMenu();
    JMenuItem menuItem = new JMenuItem("A popup menu item");
    popup.add(menuItem);
    menuItem = new JMenuItem("Another popup menu item");
    popup.add(menuItem);
    MouseListener popupListener = new MouseAdapter() {

      @Override
      public void mousePressed(MouseEvent e) {
        maybeShowPopup(e);
      }

      @Override
      public void mouseReleased(MouseEvent e) {
        maybeShowPopup(e);
      }

      private void maybeShowPopup(MouseEvent e) {
        if (e.isPopupTrigger()) {
          popup.show(e.getComponent(), e.getX(), e.getY());
          System.out.println("Componente: " + e.getComponent().getName());
        }
      }
    };
    jPanel1.addMouseListener(popupListener);
    jPanel2.addMouseListener(popupListener);
    jPanel3.addMouseListener(popupListener);
//...