java - 成员级别的匿名内部类

Question

《Java OCP 8程序员II学习指南》一书中说

an anonymous inner class is a local inner class

和

a local inner class is a nested class defined within a method

但是，我可以在方法外部定义匿名内部类:

public class Outer {
  Foo ex = new Foo {
      @Override
      public void bar() {
        System.out.println("This is my bar implementation");
      }
  }
}

void TestClass {
  public static void main(String[] args) {
    Outer outer = new Outer();
    outer.ex.bar();
  }
}

这本书说匿名内部类是本地内部类是错误的，因为它不必是本地的(在方法内)，还是我提供的示例不是匿名内部类(因为它被分配给命名变量)？

谢谢

Answer 1

ex 不是本地类。本地类不能匿名的任何内容，反之亦然(据我所知)

引用自Oracle's Java OO tutorial on Anonymous Classes :

Anonymous classes enable you to make your code more concise. They enable you to declare and instantiate a class at the same time. They are like local classes except that they do not have a name. Use them if you need to use a local class only once.

下面几行..

While local classes are class declarations, anonymous classes are expressions, which means that you define the class in another expression