Polymorphism

[Turk4n]

Yes, you must declare a method final, so i can't be overwritten.
By declaring the whole class final, it can't be extended at all.

My teacher teached "the security hole" by programming a Door, that could be opened by certain Key, and then extended a Superkey from it, which could open any Door.

final public class NoExtendingAtAll {       
    public void method(){
    	
    }   
}

public class Someclass {       
    final public void noOverwritingMethod(){
    	
    }   
}

Great to hear.

[unscripted_1]

Very helpful tut!

I would like to ask, do I have the correct understanding of polymorphism? Here's what I understand:

first, I create a class called Human, which has a generic talk() method:

public class Human {

   public void talk() {

      System.out.println("I'm a generic Human!");

   }
}

I can then create EXTENSIONS of the Human class, which override the talk() method in Human.java... This Child class does this:

public class Child extends Human {

   public void talk() {

      System.out.println("I'm a Child Human!");

   }
}

& just for good measure here's an Oldie class:

public class Oldie extends Human {

   public void talk() {

      System.out.println("I'm an ancient Human!");

   }
}

OK! Now we're ready to use our polymorphed Human classes in our program... Here's the example:

public class Tester {

   public static void main(String[] args) {

      Human[] myPeople = new Human[3];

      myPeople[0] = new Human();
      myPeople[1] = new Child();
      myPeople[2] = new Oldie();

      // lets test their overloaded methods

      for (int i = 0; i < myPeople.length; i++) {

         myPeople[i].talk();

      }

   } // end main

}

Again, thanks for the tutorial, it was very instructive!

[Sinipull]

Yes, your understanding seems to be correct.

[Turk4n]

Glad it came to hands

[GMVResources]

Nice job turk4n +rep

[Turk4n]

Nice job turk4n +rep

Thanks, and you are welcome

[farhanyun91]

may i know what package is and what is the function??

[Turk4n]

may i know what package is and what is the function??

package Polymorphism;

And function by that what do you mean?

[farhanyun91]

package Polymorphism;

And function by that what do you mean?

yeah what is package??is it for declaring?

[Turk4n]

yeah what is package??is it for declaring?

I am declaring that it is within the "fields" of "Polymorphism" folder. So by doing this I can actually just use anything there.