Answer by matsev for What is more efficient: System.arraycopy or Arrays.copyOf?

Have you looked at the Sun's implementation of Arrays.copyOf()?

 public static int[] copyOf(int[] original, int newLength) {
    int[] copy = new int[newLength];
    System.arraycopy(original, 0, copy, 0,
                     Math.min(original.length, newLength));
    return copy;
}

As can be seen, it uses System.arraycopy() internally, so the performance would be the same.