@Transactional
  public void create(ExtensionLinkEntity link)
      throws AmbariException {
    EntityManager entityManager = entityManagerProvider.get();
    entityManager.persist(link);
  }
Persists a new extension link instance.

@param link
         the extension link to persist (not {@code null}).
ambari-server/src/main/java/org/apache/ambari/server/orm/dao/ExtensionLinkDAO.java