code: public void restoreAfterSafeModeRestart() throws IOException {
      if (!clusterManager.safeMode) {
        throw new IOException("restoreAfterSafeModeRestart() called while the " +
          "Cluster Manager was not in Safe Mode");
      }
      // Restoring all the ClusterNode(s)
      for (ClusterNode clusterNode : nameToNode.values()) {
        restoreClusterNode(clusterNode);
      }
  
      // Restoring all the RequestedNodes(s)
      for (ClusterNode clusterNode : nameToNode.values()) {
        for (ResourceRequestInfo resourceRequestInfo :
          clusterNode.grants.values()) {
          // Fix the RequestedNode(s)
          restoreResourceRequestInfo(resourceRequestInfo);
          loadManager.incrementLoad(resourceRequestInfo.getType());
        }
      }
    }
docs: This method rebuilds members related to the NodeManager instance, which
  were not directly persisted themselves.
  @throws IOException