@WebListener
public class SCJMSProducerSCL implements ServletContextListener {

    private MessageService messageService;

    @Override
    public void contextInitialized(ServletContextEvent sce) {
           messageService = new MessageService();
           messageService.connect();
    }

    @Override
    public void contextDestroyed(ServletContextEvent sce) {
           messageService.close();
    }

}

@WebServlet(name = "sender", urlPatterns = {"/send"})
public class EventSender extends HttpServlet {
    
    private final MessageService messageService;

    public EventSender(MessageService messageService) {
        this.messageService = messageService;
    }
    
    @Override
    protected void doGet(
            HttpServletRequest req, 
            HttpServletResponse resp) throws ServletException, IOException {
        Event event = new Event();
        messageService.send(event);
        
        try (PrintWriter printWriter = resp.getWriter()) {
            printWriter.println("Message sent");
        }
    }

}

    @Override
    public void contextInitialized(ServletContextEvent sce) {
           messageService = new MessageService();
           messageService.connect();
    }

     sce.getServletContext().setAttribute("attrname", messageService);

   public void init(ServletConfig config) throws ServletException {
       super.init(config);
       messageService = (MessageService) config.getServletContext().getAttribute("attrname");
   }