private void loadStackVersion() {
    desiredStackVersion = new StackId(getClusterEntity().getDesiredStack());

    if (!StringUtils.isEmpty(desiredStackVersion.getStackName())
        && !StringUtils.isEmpty(desiredStackVersion.getStackVersion())) {
      try {
        loadServiceConfigTypes();
      } catch (AmbariException e) {
        // TODO recheck wrapping exception here, required for lazy loading after
        // invalidation
        throw new RuntimeException(e);
      }
    }
  }
Caches all of the {@link ClusterConfigEntity}s in {@link #allConfigs}.
ambari-server/src/main/java/org/apache/ambari/server/state/cluster/ClusterImpl.java