java中的多态是怎么体现的

多态是父类的引用指向了自己的子类对象。

当调用方法时，会根据实际的对象去调用方法

总结：变量在编译阶段绑定，方法在运行阶段绑定。属性不能重写，方法可以重写。

public class Father { 

    public void method() {
       System.out.println("父类方法，对象类型：" + this.getClass());
    } 

} 

public class Son extends Father { 

    public void method() {
           System.out.println("子类方法，对象类型：" + this.getClass());
    }   

    public static void main(String[] args) {
       Father sample = new Son();//向上转型
       sample.method();
    }
} 

父类和子类有相同的属性时

public class Person {

    public String name;

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

}

public class Student  extends Person {

    public String name;

    public String getName() {
        return name;
    }

    public Student(String name) {
        this.name = name;
        super.name = "wangwu";
    }

    public static void main(String[] args) {

        Person person =  new Student("zhangsan");
        System.out.println(person.name);   //wangwu

        System.out.println("****************");
        Student student_1 = new Student("zhangsan");
        Person person_1  = student_1;
        System.out.println("person_1.getName() :" + person_1.getName()); //zhangsan
        System.out.println("person_1.name :"+ person_1.name); //wangwu
        System.out.println("student_1.getName() :" + student_1.getName());//zhangsan
        System.out.println("student_1.name :" + student_1.name);//zhangsan

    }

}