Remember though that if you are going to make the method static any member variables that you use with in the method will also need to be static
For example:
In your code I would assume that internally you are using a collection so:
public class CatCollection
{
private static List<Cat> cats = new ArrayList<Cat>;
public CatCollection()
{
.........
}
public static void addCat(Cat aCat)
{
//adds a Cat object to an array in CatCollection
cats.add(cat);
}
}
The other thing that you need to bare in mind when doing this kind of operation is that if you do instantiate the CatCollection class there will still only be one instance of the cats collection as it is declared static.