How do I box and unbox an array

In this Q&A, we'll go over how to box and unbox an array of primitives.

Integer primitive can be boxed as below:
int ip = 0;
Integer io = ip;

But the following code results in a compile error:
int[] ia = {1,2,3,4};
Integer[] IA2 = ia;

To achieve the above, Apache commons ArrayUtils provides methods to box and unbox an array.  See code below:

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

Integer[] IA = ArrayUtils.toObject(ia);

int[] ia3 = ArrayUtils.toPrimitive(IA);

Better option - where possible - is to create an ArrayList.  That's probably the reason, Java does not provide an easy way to box or unbox primitive arrays.