public void updateExtensionLink(StackManager stackManager, ExtensionLinkEntity linkEntity, StackInfo stackInfo,
                                  ExtensionInfo oldExtensionInfo, ExtensionInfo newExtensionInfo) throws AmbariException {
    //validateUpdateExtensionLinkRequest(stackInfo, extensionInfo);
    ExtensionHelper.validateUpdateLink(stackManager, stackInfo, oldExtensionInfo, newExtensionInfo);

    ExtensionEntity extension = extensionDAO.find(newExtensionInfo.getName(), newExtensionInfo.getVersion());
    linkEntity.setExtension(extension);

    try {
      linkEntity = linkDAO.merge(linkEntity);
    } catch (RollbackException e) {
      String message = "Unable to update extension link";
      LOG.debug(message, e);
      String errorMessage = message
              + ", stackName=" + stackInfo.getName()
              + ", stackVersion=" + stackInfo.getVersion()
              + ", extensionName=" + newExtensionInfo.getName()
              + ", extensionVersion=" + newExtensionInfo.getVersion();
      LOG.warn(errorMessage);
      throw new AmbariException(errorMessage, e);
    }
  }
Updates the extension version of the currently linked extension to the stack version
ambari-server/src/main/java/org/apache/ambari/server/controller/AmbariManagementHelper.java