Efficient System.arraycopy on multidimensional arrays

Question

I\'m aware that a common performance refactoring is to replace simple for\'s by System.arraycopy.

I want to ask about:

1. Whe

Answer 1

In my use case this

public  T[][] arrayCopy(T[][] array) {

    return Arrays.stream(array).
              map(el -> el.clone()).toArray(a -> array.clone());
}

was way faster than using System.arraycopy or the straight forward two for loops solution.
Also tested with primitives ( arrayCopy(int[][] array) ) and got the same result.