Java nested classes

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Java内部类总结。

Java规范中定义了好几种内部类，但是根据 static, local, anonymous
三个区分方式就可以将所有内部类划分的明明白白。

Java nested classes

Java总共定义了4种内部类：

  • nested classes(static or not?)
    • static nested class
    • non-static nested class(local or not?)
      • member class
      • local class(anonymous or not?)
        • local class
        • anonymous class

等等，下面算是哪一种呢？

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class Outer {
    Object mObject = new Object() {
        @Override
        String toString() {
            return "WTF";
        }
    };
}

看起来像是anonymous member class啊，但是它其实是anonymous class，
看官方的定义(oracle docs)：

There are two additional types of inner classes.
You can declare an inner class within the body of a method.
These classes are known as local classes.
You can also declare an inner class within the body of a method without naming the class.
These classes are known as anonymous classes.

另外，不要忘记，field的初始化其实是在构造函数里面进行的，所以上面的mObject的初始化(new操作)
其实是在构造函数里面进行的，它是符合匿名内部类的定义的。

(over)