@Override
  public void setRegionByPath(String path, InternalRegion r) {
    if (r == null) {
      pathToRegion.remove(path);
    } else {
      pathToRegion.put(path, r);
    }
  }
Set the default pool on a new GemFireCache.
geode-core/src/main/java/org/apache/geode/internal/cache/GemFireCacheImpl.java