code: public static int sizeOf(@NotNull Object array) {
      checkNotNull(array);
      validateIsArray(array);
      return getLength(array);
    }
docs: Returns the size of the given array.
  
  @param array the array.
  @return the size of the given array.
  @throws NullPointerException     if the given array is {@code null}.
  @throws IllegalArgumentException if the given object is not an array.