# OOP/Polymorphism question

**URL:** <https://forum.kirupa.com/t/oop-polymorphism-question/285219>\
**Category:** flash\
**Created:** [March 28, 2009, 7:44pm UTC](https://forum.kirupa.com/t/oop-polymorphism-question/285219 "2009-03-28T19:44:28Z")\
**Posts on this page:** 1\
**Page:** 1

<div class="post-metadata">

**Author:** ![greetification](https://avatars.discourse-cdn.com/v4/letter/g/3bc359/32.png) [@greetification](https://forum.kirupa.com/u/greetification)\
**Post date:** [March 28, 2009, 7:44pm UTC](https://forum.kirupa.com/t/oop-polymorphism-question/285219/1 "2009-03-28T19:44:28Z")

</div>

I have an OOP question about polymorphism I was hoping someone could help me with.

Basically i’m wondering what the advantage of using an Interface is over calling a function from the constructor, for example how is this:

```auto

package {
	public class Thing {
		public function Thing() {
			init();
		}
		
		private function init():void {
		}
	}
}

```

different from:

```auto

package {
	public class Thing implements init {
		public function Thing() {
		}
		
		private function init():void {
		}
	}
}

package {
	public interface init {
		function init();
	}
}

```