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

• clone() makes a distinct copy of the first array with its own reference.
• System.arraycopy() uses JNI (Java Native Interface) to copyan array (or parts of it), so it isblazingly fast, as you can confirmhere;
• 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.

No. If you're really microbenchmarking, then maybe, depending on what JVM you're running. But in actuality, no.

I happened to look at this question when I was pondering on the same doubt. I feel that the arraycopy() is a method to be used when the array is predefined (i.e. memory is already allocated). Thus, the overhead associated with memory allocation is not repeated.

For example, imagine a case when you have defined a large array which is updated periodically. Then using clone() will recreate a array of required size every time the array is copied. However, arraycopy() uses the pre-allocated memory space.

Thus arraycopy() is more efficient in certain scenarios compared to clone(). On the other hand clone() results in a compact code.