public static void main(String[] args) {
List l1 = new ArrayList();
List l2 = new ArrayList(){};
List l3 = new ArrayList(){{}};
System.out.println(l1.getClass() == l2.getClass() );
System.out.println(l2.getClass() == l3.getClass() );
System.out.println(l1.getClass() == l3.getClass() );
}

class Sub extends ArrayList {
{
//初始化代码块
}
}
List l3 = new Sub();

List l5 = new ArrayList(5){
{
System.out.println("我是匿名内部类");
}
};

class Sub extends ArrayList{
{
System.out.println("我是匿名内部类");
}
Sub(int num){
super(num);
}
}
List l5 = new Sub(5);

package testtest; 
 
public class Main { 
 
  public static void main(String[] args) { 
    InnerTest inner = new InnerTest(); 
    Test t = inner.get(3); 
    System.out.println(t.getI()); 
  } 
} 
 
class Test { 
 
  private int i; 
 
  public Test(int i) { 
    this.i = i; 
  } 
 
  public int getI() { 
    return i; 
  } 
} 
 
class InnerTest { 
 
  public Test get(int x) { 
    return new Test(x) { 
 
      @Override 
      public int getI() { 
        return super.getI() * 10; 
      } 
    }; 
  } 
}