[rules-users] fireAllRules() doesn't return back

Hi,I'm using drools-5.3.0.Beta1. I've following rule definition: import java.util.*; declare Student    name : String @key    subjectGradeMap : HashMap    end   rule "Subject grade points" dialect "mvel" when    $u : Student() then    $u.subjectGradeMap["CompSc"] += 100;    System.out.println("Marks added"); end While executing RHS of above rule, fireAllRules() doesn't return, it hangs.Please help.Thanks,Neel