final修饰类：当一个类被final所修饰时，表示该类是一个终态类，即不能被继承。

public class FinalTest {

    public static void main(String[] args) {
    }
}

final class E {

}

class F extends E {

}

final修饰方法：当一个方法被final所修饰时，表示该方法是一个终态方法，即不能被重写（Override）

public class FinalTest2 {

    public static void main(String[] args) {
        H h = new H();
        h.output();
    }
}

class G {

    public final void output() {
        System.out.println("G");
    }
}

class H extends G {

    public void output() {
        System.out.println("H");
    }
}

final修饰属性：当一个属性被final所修饰时，表示该属性不能被改写

 public class FinalTest3{
        public static void main(String[] args){
                People people = new People();
          //  people.age = 20;  
                people.address = new Address();
           }
    }


     class People{
        //final int age = 10;  
             final Address address = new Address();
     }

     class Address{
         String name = "Beijing";
     }

没有修改final对象，只是修改对象的内容

public class FinalTest3 {

    public static void main(String[] args) {
        People people = new People();
        //  people.age = 20;  
        //  people.address = new Address();   
        people.address.name = "shanghai";
    }
}


class People {

    //final int age = 10;  
    final Address address = new Address();
}

class Address {

    String name = "Beijing";
}