@Override
  public TsFileResource get(int index) {
    int currIndex = 0;
    TsFileResource currTsFileResource = header;
    while (currIndex != index) {
      if (currTsFileResource.next == null) {
        throw new ArrayIndexOutOfBoundsException(currIndex);
      } else {
        currTsFileResource = currTsFileResource.next;
      }
      currIndex++;
    }
    return currTsFileResource;
  }
Only List type parameter is legal, because it is in order.
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/storageengine/dataregion/tsfile/TsFileResourceList.java