private void findParents(JavaClass jclass, Set<JavaClass> changedParents) {
   for (JavaClass parent : getParents(jclass)) {
     if (changedParents.add(parent)) {
       findParents(parent, changedParents);
     }
   }
 }
 // Loop through all changed classes, adding their parents (and their
 // parents)
 // to another set of changed classes
 public Set<JavaClass> findChangedParents(Set<JavaClass> classes) {
   Set<JavaClass> changedParents = Sets.newHashSet(classes);
   for (JavaClass jclass : classes) {
     findParents(jclass, changedParents);
   }
   return changedParents;
 }