J2SE Object-oriented _ method rewriting

override of Method (Overwrite/override)

classPerson {PrivateString name; Private intAge ;  Public voidSetName (String name) { This. name=name;}  Public voidSetage (intAge) { This. age=Age ;}  PublicString GetName () {returnname;}  Public intGetage () {returnAge ;}  PublicString GetInfo () {return"Name:" + name + "\ n" + "Age:" +Age ; }}classStudentextendsPerson {PrivateString School;  PublicString Getschool () {returnSchool;}  Public voidSetschool (String school) { This. School =School;}  PublicString GetInfo () {return"Name:" + getName () + "\nage:" +getage ()+ "\nschool:" +School; }} Public classTestoverwrite { Public Static voidMain (String arg[]) {Student Student=NewStudent (); Person Person=NewPerson (); Person.setname ("None"); Person.setage (1000); Student.setname ("John"); Student.setage (18); Student.setschool ("SCH");        System.out.println (Person.getinfo ());    System.out.println (Student.getinfo ()); }}

Testoverwrite.javaSuper keyword

Memory Analysis

how to construct in inheritance

classSuperclass {Private intN; /*Superclass () {System.out.println ("superclass ()"); }    */Superclass (intN) {System.out.println ("Superclass (" + n + ")");  This. N =N; }}classSubclassextendsSuperclass {Private intN; Subclass (intN) {//super ();System.out.println ("Subclass (" + n + ")");  This. N =N; } subclass () {Super(300); System.out.println ("Subclass ()"); }} Public classTestsupersub { Public Static voidMain (String arg[]) {//Subclass SC1 = new Subclass ();Subclass SC2 =NewSubclass (400); }}

Testsupersub.java

Exercise 1

Exercise 2

Object class

tostring Method

 Public class testtostring{    publicstaticvoid  main (string[] args) {        new  Dog ();        System.out.println ("d:=" +D);}    } class dog{    public  String toString () {        return "I ' m a cool dog!" ;    }}

Testtostring.javaEquals Method

 Public classtestequals{ Public Static voidMain (string[] args) {Cat C1=NewCat (All-in-); Cat C2=NewCat (All-in-); SYSTEM.OUT.PRINTLN (C1==C2);  System.out.println (c1.equals (C2)); //rewrite before the same as above    }}classcat{intcolor; intheight, weight;  PublicCat (intColorintHeightintweight) {         This. color =color;  This. Height =height;  This. Weight =weight; }    Public Booleanequals (Object obj) {if(obj = =NULL)return false; Else{      if(objinstanceofCat) {Cat C=(Cat) obj; if(C.color = = This. color && C.height = = This. height && C.weight = = This. Weight) {                return true; }       }     }     return false; }}                            

Testequals.java

J2SE Object-oriented _ method rewriting