code: private MethodHandle findConstructor() {
      try {
        MethodHandle mh = MethodHandles.publicLookup().findConstructor(clazz,
            MethodType.methodType(void.class, getIdType()));
        return mh;
      } catch (NoSuchMethodException | IllegalAccessException exp) {
        String pattern = "Class %s requires a public constructor with one parameter of type %s";
        String error = String.format(pattern, clazz.getName(), getIdType());
        throw new EntityManagerException(error, exp);
      }
    }
docs: Creates and returns the MethodHandle for the constructor.
  
  @return the MethodHandle for the constructor.