how to configur my realm security in weblogic sever 12c

Hello; I created a security domain (Realm) that I named XXRealm, in this last one I created users with providers (Provider). And in the deployment descriptor (WEB.XML) of my application I have specifies the realm to use (XXRealm), but the problem is that when I authenticate, my application compares the user and the password with the users created in the security domain (MyRealm) the one by default of weblogic and it ignores my realm to me (XXRealm). My question is how I can force weblogic to use my realm (XXRealm specified in web.xml) and stop using the one default (myRealm).