Dynamic dispatch

[Prakash Rai]

class A{
void show(){
System.out.println("Class A ");
}
}
class B extends A{
	void show1(){
		System.out.println("Class B ");
	}
}
class Main{
public static void main(String arg[]){
A a1=null;
a1=new B();
//a1.show1();
a1.show();
}
}

1. Here in dynamic dispatch I am assigning Object of subclass assigned to super class reference variable. What is the advantages of doing this.?

[Funkaj Kohli]

To see the benefit of dynamic dispatch in your example, re-name the functions in both the classes to "show()"

Then use this code in your main :

public static void main(String[] ar) {
    A a = new A();
    a.show();

    a = new B();
    a.show();
}

[Prakash Rai]

That super class method will be called....

Funkaj Kohli wrote:To see the benefit of dynamic dispatch in your example, re-name the functions in both the classes to "show()"

Then use this code in your main :

public static void main(String[] ar) {
    A a = new A();
    a.show();

    a = new B();
    a.show();
}

[Prakash Rai]

class Animal{
	static void eating(){
	System.out.println("Animal is eating");
	}
 void sleeping(){
	System.out.println("Animal is sleeping");
	}
}
class Cat extends Animal{
  static void eating(){
	System.out.println("Cat is eating ");
}
void sleeping(){
	System.out.println("Dog is sleeping");
}
}
class Test6{
	public static void main(String arg[]){
	Animal a=new Cat();
	a.eating();//1. Animal is eating
	a.sleeping();//2. Dog is sleeping
	}
}

1. Here I am overriding Static method eating() in sub class even it is calling super classs eating().
2. Here it calling subclass Overridden sleeping(). why?
3. Will it differ from static method and instance method in case of dynamic dispatch?

[Seetharaman Venkatasamy]

Hi Prakash Rai ,
please start a new thread for a new/each question. so that you can get more response due to the clear subject line

[Seetharaman Venkatasamy]

Coming to your question, search first here in javaranch.
Anyway, i did for you this time .
1.https://coderanch.com/t/409544/java/java/we-override-static-method

2.google link

[Campbell Ritchie]

Prakash Rai wrote: . . . I am overriding Static method eating() . . .

No you aren't You can only override instance methods. Nothing else can be overridden. With static methods you get static dispatch, ie on the class the object is declared as. You might call that static dispatch, and it's why you call them static.

And never call static members on the name of the object. Call them on the name of the class.

[Jesper de Jong]

I already answered the question about static methods in your other topic.