@Override
  public <K, V> Region<K, V> basicCreateRegion(String name, RegionAttributes<K, V> attrs)
      throws RegionExistsException, TimeoutException {
    try {
      InternalRegionArguments ira = new InternalRegionArguments()
          .setDestroyLockFlag(true)
          .setRecreateFlag(false)
          .setSnapshotInputStream(null)
          .setImageTarget(null);

      if (attrs instanceof UserSpecifiedRegionAttributes) {
        ira.setIndexes(((UserSpecifiedRegionAttributes<?, ?>) attrs).getIndexes());
      }
      return createVMRegion(name, attrs, ira);
    } catch (IOException | ClassNotFoundException e) {
      throw new InternalGemFireError("unexpected exception", e);
    }
  }
Set the default pool on a new GemFireCache.
geode-core/src/main/java/org/apache/geode/internal/cache/GemFireCacheImpl.java