@Override
 public void inform(final SolrCore core) {
   if (!(core.getResourceLoader() instanceof ZkSolrResourceLoader)) return;
   final ZkSolrResourceLoader zkSolrResourceLoader =
       (ZkSolrResourceLoader) core.getResourceLoader();
   if (zkSolrResourceLoader != null)
     zkSolrResourceLoader
         .getZkController()
         .registerConfListenerForCore(
             zkSolrResourceLoader.getConfigSetZkPath(),
             core,
             getListener(core, zkSolrResourceLoader));
 }
  private static Runnable getListener(SolrCore core, ZkSolrResourceLoader zkSolrResourceLoader) {
    final String coreName = core.getName();
    final CoreContainer cc = core.getCoreDescriptor().getCoreContainer();
    final String overlayPath =
        zkSolrResourceLoader.getConfigSetZkPath() + "/" + ConfigOverlay.RESOURCE_NAME;
    final String solrConfigPath =
        zkSolrResourceLoader.getConfigSetZkPath() + "/" + core.getSolrConfig().getName();
    String schemaRes = null;
    if (core.getLatestSchema().isMutable()
        && core.getLatestSchema() instanceof ManagedIndexSchema) {
      ManagedIndexSchema mis = (ManagedIndexSchema) core.getLatestSchema();
      schemaRes = mis.getResourceName();
    }
    final String managedSchmaResourcePath =
        schemaRes == null ? null : zkSolrResourceLoader.getConfigSetZkPath() + "/" + schemaRes;
    return new Runnable() {
      @Override
      public void run() {
        log.info("config update listener called for core {}", coreName);
        SolrZkClient zkClient = cc.getZkController().getZkClient();
        int solrConfigversion, overlayVersion, managedSchemaVersion = 0;
        SolrConfig cfg = null;
        try (SolrCore core = cc.getCore(coreName)) {
          if (core.isClosed()) return;
          cfg = core.getSolrConfig();
          solrConfigversion = core.getSolrConfig().getOverlay().getZnodeVersion();
          overlayVersion = core.getSolrConfig().getZnodeVersion();
          if (managedSchmaResourcePath != null) {
            managedSchemaVersion =
                ((ManagedIndexSchema) core.getLatestSchema()).getSchemaZkVersion();
          }
        }
        if (cfg != null) {
          cfg.refreshRequestParams();
        }

        if (checkStale(zkClient, overlayPath, solrConfigversion)
            || checkStale(zkClient, solrConfigPath, overlayVersion)
            || checkStale(zkClient, managedSchmaResourcePath, managedSchemaVersion)) {
          log.info("core reload {}", coreName);
          cc.reload(coreName);
        }
      }
    };
  }