@Override
    public int linkedList(int entry) {
      // base  = JAVA64_OBJECT + PRIMITIVES1 * 2 + JAVA64_FIELDREF;
      // entry = JAVA64_OBJECT + JAVA64_FIELDREF * 2
      return linkedListBase() + linkedListEntry() * entry;
     }
Estimation of memory footprint of object
storage-api/src/java/org/apache/hadoop/hive/ql/util/JavaDataModel.java