public StackReleaseVersion getReleaseVersion() {

    if (StringUtils.isNotEmpty(releaseVersionClass)) {
      try {
        return getLibraryInstance(releaseVersionClass);
      } catch (Exception e) {
        LOG.error("Could not create stack release instance.  Using default. {}", e.getMessage());
        return new DefaultStackVersion();
      }
    } else {
      return new DefaultStackVersion();
    }
  }
Gets the instance of the {@code StackReleaseVersion}.  If not specified
or there is an error instantiating the class, return a default implementation.

@return the stack release information.
ambari-server/src/main/java/org/apache/ambari/server/state/StackInfo.java