You will never instantiate this class directly, but always create an instance of its subclass.

永远不要直接实例化这个类，而是创建它的子类的一个实例。

youdao

Instantiate a callback handler instance.

实例化一个回调处理程序实例。

youdao

The class also must have a no-arg constructor which will be used by Flex to instantiate an instance.

这个类还必须具有一个 no-arg 构造函数，该函数将被 Flex 用来实例化一个实例。

youdao

This is what's actually going to create the instance, instantiate it, create what the set of variable values are for it.

这个声明在你,创建一个实例的时候，实例化这个实例,然后给这个实例。

麻省理工公开课 - 计算机科学及编程导论课程节选