code: public static <T> T[] validIndex(final T[] array, final int index) {
          return validIndex(array, index, DEFAULT_VALID_INDEX_ARRAY_EX_MESSAGE, Integer.valueOf(index));
      }
docs: <p>Validates that the index is within the bounds of the argument
  array; otherwise throwing an exception.</p>
  
  <pre>Validate.validIndex(myArray, 2);</pre>
  
  <p>If the array is {@code null}, then the message of the exception
  is &quot;The validated object is null&quot;.</p>
  
  <p>If the index is invalid, then the message of the exception is
  &quot;The validated array index is invalid: &quot; followed by the
  index.</p>
  
  @param <T> the array type
  @param array  the array to check, validated not null by this method
  @param index  the index to check
  @return the validated array (never {@code null} for method chaining)
  @throws NullPointerException if the array is {@code null}
  @throws IndexOutOfBoundsException if the index is invalid
  @see #validIndex(Object[], int, String, Object...)
  
  @since 3.0