The difference is that Arrays.copyOf
does not only copy elements, it also creates a new array. System.arraycopy
copies into an existing array.
Here is the source for Arrays.copyOf
, as you can see it uses System.arraycopy
internally to fill up the new array:
public static <T,U> T[] copyOf(U[] original, int newLength, Class<? extends T[]> newType) {
T[] copy = ((Object)newType == (Object)Object[].class)
? (T[]) new Object[newLength]
: (T[]) Array.newInstance(newType.getComponentType(), newLength);
System.arraycopy(original, 0, copy, 0,
Math.min(original.length, newLength));
return copy;
}