The Java-UML Lightweight Enumerator (JULE) tool implements a vitally important aspect of the framework for software tool certification - test suite generation. The framework uses UML models as the test inputs for the bounded exhaustive-testing approach. Within a size bound for the metamodel types, JULE enumerates only the set of nonisomorphic models in the form of relational structures. These models are classified into two sets - demonstration and counterexample - using Binary Decision Diagrams (BDDs). The power of JULE lies in its model enumeration and its use of a high-performance grid infrastructure. Hence, JULE efficiently generates a very small test suite while increasing the bound on the input size to the extent that is practical for certification purpose.