Is there any reason to prefer System.arraycopy() over clone()?

Question

clone() makes a distinct copy of the first array with its own reference.
System.arraycopy() uses JNI (Java Native Interface) to copy
an array (or parts of it), so it is
blazingly fast, as you can confirm
here;
clone() creates a new array with the same characteristics as the old array, i.e., same size, same type, and same contents. Refer to here for some examples of clone in action;
manual copying is, well, manual copying. There isn’t much to say about this method, except that many people have found it to be the most performant.
arraynew = arrayold doesn’t copy the array; it just points arraynew to the memory address of arrayold or, in other words, you are simply assigning a reference to the old array.