code: public static String getConstructorDescriptor(final Constructor<?> constructor) {
      StringBuilder stringBuilder = new StringBuilder();
      stringBuilder.append('(');
      Class<?>[] parameters = constructor.getParameterTypes();
      for (int i = 0; i < parameters.length; ++i) {
        appendDescriptor(stringBuilder, parameters[i]);
      }
      return stringBuilder.append(")V").toString();
    }
docs: Returns the descriptor corresponding to the given constructor.
  
  @param constructor a {@link Constructor} object.
  @return the descriptor of the given constructor.