code: @Nullable
    public static String getAsStringRFC822 (@Nullable final OffsetDateTime aDateTime)
    {
      if (aDateTime == null)
        return null;
      return getAsStringRFC822 (aDateTime.toZonedDateTime ());
    }
docs: create a RFC822 representation of a date.
  
  @param aDateTime
  Date to print. May be <code>null</code>.
  @return the RFC822 represented by the given Date. <code>null</code> if the
  parameter is <code>null</code>.