First, Please forgive me for my clumsy English.
[What I want to do]
I want to know
@Path annotation defines a path to a RESTful Web service so when you have @Path("/SomeService") it will translate into www.yourapp.com/baseRestUrl/SomeService. You can also define it on the methods which provides REST services. Note that baseRestUrl is defined inside web.xml or in class which extends Application class.
On the other hand @WebServlet("/SomePath") states that Servlet will be listening for request on the www.yourapp.com/SomePath, it is basically replacement of servlet-mapping element in web.xml. You can still configure servlets like this, it's up to you whether you prefer XML or annotation configuration.