Its a difficult answer if you come from a Pascal (Delphi), C or C++ back ground where you had to initialize the array first with default values like 0 before using.
Java automatically initialize all elements in an array to default values, object references become null and primitive integers become 0.
This is in my SCJP exam studies, tricky since I come from a Pascal and C++ back ground.
In C/C++ you get some random data (whatever is in memory at that pointer address). So for them you need to initialize the array before use.