for (int i = 0; i*2 < arr.length; i++)
{
    int c = arr[i];
    arr[i] = arr[arr.length - i - 1];
    arr[arr.length - i - 1] = c;
}

for (int i = 0; i < arr.length; i++)
    System.out.print(arr[i] + " ");
System.out.println();