# Memory management question

**URL:** https://forum.kirupa.com/t/memory-management-question/307221
**Category:** Uncategorized
**Created:** [March 30, 2010, 9:37pm UTC](https://forum.kirupa.com/t/memory-management-question/307221 "2010-03-30T21:37:13Z")
**Posts on this page:** 1
**Page:** 1

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### Author: ![SmoothDime](https://avatars.discourse-cdn.com/v4/letter/s/6de8d8/32.png) [@SmoothDime](https://forum.kirupa.com/u/SmoothDime)
#### Post date: [March 30, 2010, 9:37pm UTC](https://forum.kirupa.com/t/memory-management-question/307221/1 "2010-03-30T21:37:13Z")

</div>

If I have something like this:

```auto

package {
   import flash.display.Sprite;

   public class Car extends Sprite {
      private var _engine:Sprite;

      public function Car(engine:Sprite = null) {
         this.engine = engine;
      }

      public function set engine(engine:Sprite):void {
         if(_engine) {
            removeChild(_engine);
         }

         //_engine = null;
         _engine = engine;
         addChild(_engine);
      }
   }
}

```

is it necessary to put

\_engine = null;

right before

\_engine = engine;

?