@Override
  public DiskStoreImpl getOrCreateDefaultDiskStore() {
    DiskStoreImpl result = (DiskStoreImpl) findDiskStore(null);
    if (result == null) {
      synchronized (this) {
        result = (DiskStoreImpl) findDiskStore(null);
        if (result == null) {
          result = (DiskStoreImpl) createDiskStoreFactory().create(defaultDiskStoreName);
        }
      }
    }
    return result;
  }
Used by unit tests to allow them to change the default disk store name.
geode-core/src/main/java/org/apache/geode/internal/cache/GemFireCacheImpl.java