Declaring arrays without using the 'new' keyword in Java

Question

Is there any difference between the following two declarations?

int arr[] = new int [5]; 

and

int arr1[] = {1,2,3,4,5}; 

Is arr1 declared on stack or on the heap?

Answer 1

There is the obvious difference that one has all zeros, and the other contains [1..5].

But that's the only difference. Both are 5-element int arrays, both are allocated in the same way. It is mere syntactic convenience to declare with the braces and no new.

Note that this form can only be used when the array is declared:

int[] blah = {} 

But not

int[] blah; blah = {}; 

or

return {}; 

Objects (arrays are objects) are allocated on the heap.