Creating objects and efficiency

Question

I am implementing bounding circles for my game and I have a question. I have heard that creating a new object takes up a lot of time (i.e doing it every update). Should I give each of my objects a BoundingSphere instance variable (I created my own simple BoundingSphere class), update it's position every update along with the sprite, or should I remove the instance variable and just return a new BoundingSphere when it is requested?
Just to clarify:
Implementation 1:
private BoundingSphere s;
public BoundingSphere getBoundingSphere() {
   return s;
//update s each time sprite is updatedImplementation 2:
//no private instance variable
public BoundingSphere getBoundingSphere() {
   return new BoundingSphere(radius, x, y);

Answer 1

If you know a maximum bound on how many of the created objects you'll need at any given time, you can prevent lots of object creation by implementing an object pool. The pool keeps a list of pre-constructed objects, and to use it, a method may request an object, use a method to initialize its values (not a constructor), then release it back to the pool when it is done using it. This is usually done with Threads to limit the number of them running, but it can be done with any object.
I hope this helps
-JBoeing