code: public ValidationWarnings validate(ICalVersion version) {
  		List<WarningsGroup> warnings = validate(new ArrayList<ICalComponent>(0), version);
  		return new ValidationWarnings(warnings);
  	}
docs: <p>
  Checks this iCalendar object for data consistency problems or deviations
  from the specifications.
  </p>
  <p>
  The existence of validation warnings will not prevent the iCalendar
  object from being written to a data stream. Syntactically-correct output
  will still be produced. However, the consuming application may have
  trouble interpreting some of the data due to the presence of these
  warnings.
  </p>
  <p>
  These problems can largely be avoided by reading the Javadocs of the
  component and property classes, or by being familiar with the iCalendar
  standard.
  </p>
  @param version the version to validate against
  @return the validation warnings