You can assign an id to the object that represents its location in the array, but if you're already iterating through in the main program why dont check there?

nardove, as soon as an object has removed itself from the array list, all the objects after this one will have incorrect ids...
jun.jk, you can use the indexOf method to find where the object is in the array list, but as nardove said, it is better to delete the objects from the parent: it is seen as bad style for an object to know in which container it is stored (and it can be actually contained in several containers!).

Yeah, I don't think it's necessary for the Object to know what ArrayList it's in, or even to have IDs. You can just test for this in your main draw() loop. Here's an example from one of my programs.

for (Iterator
              
               <Drawing> i = drawingList.iterator(); i.hasNext();) {
    Drawing d = i.next();
    
               if (d.isOffScreen(
              this
              
               )) {
        i.remove();
    }
    
               else {
        d.run();
    }
}