Set<RefClass> (RefClass refClass) { final Set<RefClass> dependents = refClass.getUserData(DEPENDENT_CLASSES_KEY); if (dependents != null) { return dependents; } final Set<RefClass> newDependents = new HashSet<>(); tabulateDependentClasses(refClass, newDependents); newDependents.remove(refClass); refClass.putUserData(DEPENDENT_CLASSES_KEY, newDependents); return newDependents; }