code: private boolean isCtFieldACollection(CtField ctField) {
          try {
              return ctField.getType().equals(cp.get(Collection.class.getName()))
                      || ctField.getType().equals(cp.get(List.class.getName()))
                      || ctField.getType().equals(cp.get(Set.class.getName())) ;
          } catch (NotFoundException e) {
              e.printStackTrace();
              return false;
          }
      }
docs: Verify that CtField is exactly the java.util.Collection, java.util.List or java.util.Set, otherwise cannot instrument the class' field