@Override
  public Set subregions(boolean recursive) {
    if (recursive) {
      throw new UnsupportedOperationException(
          "Getting subregions recursively is not supported.");
    }

    return new HashSet(subregions.values());
  }
Adds a subregion with the given name to this region


@throws RegionExistsException If a subregion with <code>name</code> already exists
geode-core/src/main/java/org/apache/geode/internal/cache/xmlcache/RegionCreation.java