new 类名或接口名(){
  public void show(){
  ···
  }
};

package newTest2;
public interface swim {
    public abstract void swim();
}

package newTest2;
public class test1 {
    public static void main(String[] args) {
        new swim(){
            @Override
            public void swim() {
                System.out.println("自由泳");
            }
        }.swim();
    }
}

interface Swim {
    public abstract void swimming();
}

public class test {
    public static void main(String[] args) {
        // 普通方式传入对象
        // 创建实现类对象
        Student s = new Student();
        goSwimming(s);
        // 匿名内部类使用场景:作为方法参数传递
        Swim s3 = new Swim() {
            @Override
            public void swimming() {
                System.out.println("蝶泳...");
            }
        };
        // 传入匿名内部类
        goSwimming(s3);
        // 完美方案: 一步到位
        goSwimming(new Swim() {
            public void swimming() {
                System.out.println("大学生, 蛙泳...");
            }
        });
        goSwimming(new Swim() {
            public void swimming() {
                System.out.println("小学生, 自由泳...");
            }
        });
    }
    // 定义一个方法,模拟请一些人去游泳
    public static void goSwimming(Swim s) {
        s.swimming();
    }
}