private Object[] createSubCache(int numEntries) {
    return new Object[numEntries];
  }
LlapObjectSubCache. A subcache which lives inside the LlapObjectCache.
The subcache maintains two lists
1. List of softreference to the objects
2. List of locks to access the objects.
ql/src/java/org/apache/hadoop/hive/ql/exec/tez/LlapObjectSubCache.java