public class Anonymous {{System.out.println("代码块:"+this.getClass().getName());}public Anonymous() {System.out.println("无参构造函数:"+this.getClass().getName());}
}
class aaa{public aaa() {Anonymous n = new Anonymous(){{System.out.println("Anonymous匿名类:"+this.getClass().getName());}};System.out.println("n:"+n.getClass().getName());List<String> list_1 = new ArrayList<String>(){{System.out.println("List匿名类:"+this.getClass().getName());}};System.out.println("list_1:"+list_1.getClass().getName());List<String> list_2 = new ArrayList<String>();System.out.println("list_2:"+list_2.getClass().getName());}
}

public class AnonymousTest {@Testpublic void test1() {Anonymous n = new Anonymous(){{System.out.println("Anonymous匿名类:"+this.getClass().getName());}};System.out.println("n:"+n.getClass().getName());List<String> list_1 = new ArrayList<String>(){@Overridepublic int size() {System.out.println("size");return super.size();}{System.out.println("List匿名类:"+this.getClass().getName());}};System.out.println("list_1:"+list_1.getClass().getName());System.out.println(list_1.size());List<String> list_2 = new ArrayList<String>();System.out.println("list_2:"+list_2.getClass().getName());}@Testpublic void test2(){System.out.println("--------------------");aaa a = new aaa();}
}

输出:

代码块:test.AnonymousTest$1
无参构造函数:test.AnonymousTest$1
Anonymous匿名类:test.AnonymousTest$1
n:test.AnonymousTest$1
List匿名类:test.AnonymousTest$2
list_1:test.AnonymousTest$2
size
0
list_2:java.util.ArrayList
--------------------
代码块:test.aaa$1
无参构造函数:test.aaa$1
Anonymous匿名类:test.aaa$1
n:test.aaa$1
List匿名类:test.aaa$2
list_1:test.aaa$2
list_2:java.util.ArrayList

总结:

代码块写在那个类,就是那个类的匿名类

结果相当于匿名类继承原有类,并且覆盖方法