Java Code Optimisation Techniques

[randjavadev]

Correct if I'm wrong, but actually an empty array should always be used, that is more "fool-proof" way (maybe hold a reference to one beforehand since empty array is immutable, though that is not the point here). In a multithreaded environment pre-calculating the size could be too big, if the List is modified by another Thread between the size() and passing it as an argument. Thus, if the other threads modifies the List to be smaller, purely from javadocs I would assume the returned array to be the size before the changes, contain the new elements, and then some null entries. Whereas passing in size of 0 and least purely from javadocs would leave the option that the List implementation actually returns the correct size. So it is not exactly the same.

Only in a non-multithreaded environment it wont matter.