difference between new type[0] and null - java

Question

What is the difference between

type[] a = new type[0];

and

type[] a = null;

Do either forms occupy any memory ? Are there any similarities / differences ?

Answer 1

The first one (new type[0]) will actually create an array object (and therefore occupy memory). You can use the (0-sized) array object, for example to get its length or iterate over it, but you can, of course, not access any of its elements. So you can pass it to any function that doesn't make assumptions about the array's length (but does the proper checks instead) and it will work.

The second one (null) doesn't create any object. You will get an exception, if you try to access any member.