jpa - Why can't I catch EJB exceptions? -

i can't seem catch exceptions such noresultexception or ejbexception in java ee 6 project. there doing wrong? have caught exceptions outside ejb container first time using ejb. thanks.

@stateless public class userejb {      @persistencecontext     entitymanager em;      public string getusername(user user) {         return user.getname();     }      public user fetchuserbyemail(string email) {          user user = em.createnamedquery("user.findbyemail", user.class).setparameter("email", email).getsingleresult();         return user;     }      public user fetchuserbyid(int id) {         return em.createnamedquery("user.findbyuserid", user.class).setparameter("userid", id).getsingleresult();     }      public list<user> fetchallusers() {         return em.createnamedquery("user.findall", user.class).getresultlist();     } }  @named(value = "usercontroller") @requestscoped public class usercontroller {      private user user = new user();     @ejb     userejb userejb;     @inject     securitycontroller securitycontroller;      public usercontroller() {     }      public void login(actionevent event) {          try {               user userlogin = userejb.fetchuserbyemail(user.getemail());          } catch (exception e) {          }          if (userlogin.getpassword().equals(user.getpassword())) {             securitycontroller.setisloggedin(true);             securitycontroller.setisadmin(true);             securitycontroller.setuser(user);         }     }      /**      * @return user      */     public user getuser() {         return user;     }      /**      * @param user user set      */     public void setuser(user user) {         this.user = user;     } 

what if put 2 system.out.printlns in code? 1 in exception handler , 1 right before if statement. get?

looking @ code would able catch exception, should jpa exception wrapped in ejb one.