code: public Type getParameterizedType() {
          Type tmp = parameterTypeCache;
          if (null == tmp) {
              tmp = executable.getAllGenericParameterTypes()[index];
              parameterTypeCache = tmp;
          }
  
          return tmp;
      }
docs: Returns a {@code Type} object that identifies the parameterized
  type for the parameter represented by this {@code Parameter}
  object.
  
  @return a {@code Type} object identifying the parameterized
  type of the parameter represented by this object