Adds all the elements of the given arrays into a new array.
The new array contains all of the element of
array1 followed
by all of the elements
array2. When an array is returned, it is always
a new array.
ArrayUtils.addAll(null, null) = null
ArrayUtils.addAll(array1, null) = cloned copy of array1
ArrayUtils.addAll(null, array2) = cloned copy of array2
ArrayUtils.addAll([], []) = []
ArrayUtils.addAll([null], [null]) = [null, null]
ArrayUtils.addAll(["a", "b", "c"], ["1", "2", "3"]) = ["a", "b", "c", "1", "2", "3"]