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