@RequiresSession
  public ServiceComponentDesiredStateEntity findById(long id) {
    return entityManagerProvider.get().find(ServiceComponentDesiredStateEntity.class, id);
  }
Gets a {@link ServiceComponentDesiredStateEntity} by its PK ID.

@param id
         the ID.
@return the entity or {@code null} if it does not exist.
ambari-server/src/main/java/org/apache/ambari/server/orm/dao/ServiceComponentDesiredStateDAO.java