public ObjectContainer getMatchfileObjContainer() {
      if (matchfileObjContainer == null) {
        matchfileObjContainer = new ObjectContainer(spillLocalDirs);
      }
      return matchfileObjContainer;
    }
This class encapsulates the triplet together since they are closely related to each other
The triplet: hashmap (either in memory or on disk), small table container, big table container
ql/src/java/org/apache/hadoop/hive/ql/exec/persistence/HybridHashTableContainer.java