@RequiresSession
  public ExtensionEntity find(String extensionName, String extensionVersion) {
    TypedQuery<ExtensionEntity> query = entityManagerProvider.get().createNamedQuery(
        "ExtensionEntity.findByNameAndVersion", ExtensionEntity.class);

    query.setParameter("extensionName", extensionName);
    query.setParameter("extensionVersion", extensionVersion);

    return daoUtils.selectOne(query);
  }
Gets the extension that matches the specified name and version.

@return the extension matching the specified name and version or {@code null}
        if none.
ambari-server/src/main/java/org/apache/ambari/server/orm/dao/ExtensionDAO.java