This code means , files under /Beer/UpdateRecipes directory is contarined resurce for member role that tooonly for POST method .
but it can be accessible to other roles (not member), other http methods (not POST) and member role with other http methods(other than POST) unconstrained manner.
Note : all roles and http methods will access the resources. But it can be constrained for some roles and methods.We can't say this resource cant be accessed.
The resource can be accessed by members of other roles with constraint through HTTP methods (other than POST). But here is the thing, your servlet won't override doXXX() except for the doPost().
No other methods and roles apart from defined are not constrained ,provided you trying to send a GET request and you have defined a doGet method,It would work fine.but if there is not doGet method, you would get the default 405 error code.