About Java polymorphism

What is polymorphic

The same implementation interface that uses different instances to perform different operations

A rule that converts a subclass into a parent class:

* When a reference to a parent class is directed to a subclass object, referred to as up transformation, automatic type conversion

* The method that is called by the parent class reference variable is a subclass that overrides or inherits the parent class's method, not the parent class's method

* You cannot call a subclass-specific method by referencing a variable from the parent class

/** pet, Dog and Penguin parent class*/Package cn.yy.test01; Public Abstract classPet {PrivateString name; Private intHealth ; Private intLove ;  PublicString GetName () {returnname; }     Public voidsetName (String name) { This. Name =name; }     Public intGethealth () {returnHealth ; }     Public voidSethealth (intHealth ) {         This. Health =Health ; }     Public intGetlove () {returnLove ; }     Public voidSetlove (intLove ) {         This. Love =Love ; }         Public Abstract voideat ();}

Package cn.yy.test01;/** * * Dog class * @author CKW **/ Public classDog extends Pet {PrivateString strain;//Variety             PublicString Getstrain () {returnstrain; }     Public voidSetstrain (String strain) { This. Strain =strain; }     PublicDog (String name,string strain) {super ();  This. Strain =strain; }     PublicDog () {super (); //TODO auto-generated Constructor stub    }    /** * to achieve a dog meal method **/@Override Public voideat () {}}

Package cn.yy.test01;/** * Penguin class * @author CKW **/ Public classPenguin extends Pet {PrivateString sex;//Sex         PublicString Getsex () {returnsex; }     Public voidsetsex (String sex) { This. Sex =sex; }    /** * To achieve the Penguin meal method*/@Override Public voideat () {//TODO auto-generated Method Stub    }}

Package cn.yy.test01;/** * Lord Human * @author CKW **/ Public classMaster {PrivateString name="";//Master Name    Private intmoney=0;//Number of ingot         PublicString GetName () {returnname; }     Public voidsetName (String name) { This. Name =name; }     Public intGetmoney () {returnMoney ; }     Public voidSetmoney (intMoney ) {         This. Money =Money ; }     PublicMaster (String name,intMoney ) {         This. name=name;  This. money=Money ; }        /** The owner feeds the pet*/     Public voidFeed (Pet Pet) {pet.eat (); }        //The owner feeds the dog .     Public voidFeed (dog dog) {dog.eat (); }        //The host feeds Penguin .     Public voidFeed (Penguin pgn) {pgn.eat (); }            }

Package cn.yy.test01; Public classTest { Public Static voidMain (string[] args) {//TODO auto-generated Method StubDog dog=NewDog ("even even","Snow Rena"); //Penguin penguin=new Penguin ();Master master=NewMaster ("Mr. Wang", -); Master.feed (dog);//The owner feeds the dog .            }}

About Java polymorphism