@Transactional
  public ClusterConfigEntity merge(ClusterConfigEntity clusterConfigEntity) {
    return merge(clusterConfigEntity, false);
  }
Merge the specified entity into the current persistence context.

@param clusterConfigEntity
         the entity to merge (not {@code null}).
@return the managed entity which was merged (never {@code null}).
ambari-server/src/main/java/org/apache/ambari/server/orm/dao/ClusterDAO.java