Connection between Parent & Child
package BindingTest3;
class Parent
{
int x=100;
void method()
{
System.out.println("Parent Method");
}
}
class Child extends Parent
{
int x=200;//this.x!=super.x
@Override
void method()
{
System.out.println("Child Method");
System.out.println("this.x: "+this.x);
System.out.println("super.x: "+super.x);
}
}
public class BindingTest3 {
public static void main(String[] args) {
// TODO Auto-generated method stub
Parent p=new Child();
Child c=new Child();
System.out.println("p.x= "+p.x);
p.method();
System.out.println();
System.out.println("c.x= "+c.x);
c.method();
}
}
package BindingTest2;
class Parent
{
int x=100;
void method()
{
System.out.println("Parent Method");
}
}
class Child extends Parent
{
}
public class BindingTest2 {
public static void main(String[] args) {
// TODO Auto-generated method stub
Parent p=new Child();//casting
Child c=new Child();
/*
*
* IN CHILD CLASS,
* "NO MEMBER VARIABLE 'x'"
*
* SO, IN THIS TIME, PARENT.X IS INHERITED TO
* CHILD CLASS WITHOUT CHANGE(VALUE)
*
* SO!! THIS.X==SUPER.X
*
* PLUS!
* WE DIDN'T DO @OVERRIDE
*
* SO!! THIS.METHOD()==SUPER.METHOD()
*/
System.out.println("p.x= "+p.x);
p.method();
System.out.println("c.x= "+c.x);
c.method();
}
}
- DIFFERENCE IS BASED ON 'WHETHER RE-DEFINE(RE-USE) MEMBER VALUE/METHOD OR NOT!'
-
Case I: didn't do re-define about member or method in child class
-
this.x==super.x
-
Case II: did re-define about member or method in child class
- this.x!=super.x
- MEMBER VAR FOLLOWS REFERENCE VARIABLE
- METHOD FOLLOWS INSTANCE