code: public static DateTime toDateTime(Timestamp value) {
          if (value == null) {
              return null;
          } else {
              return new DateTime(value.getTime(), DateTimeZone.UTC);
          }
      }
docs: Null-safe method of converting a SQL Timestamp into a DateTime that
  it set specifically to be in UTC.
  <br>
  NOTE: The timestamp also should be in UTC.
  @return A UTC DateTime