code: public static OffsetDateTime getCreationTime(long entityId)
      {
          long timestamp = (entityId >>> TIMESTAMP_OFFSET) + DISCORD_EPOCH;
          Calendar gmt = Calendar.getInstance(TimeZone.getTimeZone("GMT"));
          gmt.setTimeInMillis(timestamp);
          return OffsetDateTime.ofInstant(gmt.toInstant(), gmt.getTimeZone().toZoneId());
      }
docs: Gets the creation-time of a JDA-entity by doing the reverse snowflake algorithm on its id.
  This returns the creation-time of the actual entity on Discords side, not inside JDA.
  
  @param  entityId
  The id of the JDA entity where the creation-time should be determined for
  
  @return The creation time of the JDA entity as OffsetDateTime