Is it OK not to specify class name with @WebListener (unlike @WebServlet)?

Question

Do I ever have to specify class name for @WebListener annotation like I have to do for @WebServlet("/MyClassname") ?

In my application just @WebListener works fine, but I have only single ServletContextListener - maybe if I had a few it would have been different?

@WebServlet("/MyServlet")
public class MyServlet extends HttpServlet {
...
}

@WebListener
public class InitWebAppServlet implements ServletContextListener {
...
}

Answer 1

The value in @WebServlet is not a class name. It is a URL path. When using only a single parameter like you show it is the equivalent of:

@WebServlet(urlPatterns = {"/MyServlet"})

Your code could just as easily have been:

@WebServlet("/bobsyouruncle")
public class MyServlet extends HttpServlet {
...
}

That means that you'd access your servlet with the url /bobsyouruncle instead of /MyServlet. See the WebServlet javadocs for more details. Note that for annotations if you have only a single parameter it sets the element value.

The optional value of the @WebListener parameter is for a description of the listener (see the WebListener javadocs). It is, again, not a class name. You can have as many @WebListener classes as you'd like though by using the annotation method instead of the web.xml method you cannot guarantee the order in which the servlet container runs them.