public int createId(Object object) {
    assert !objectToID.containsKey(object);
    int id = ++highestID;
    objectToID.put(object, id);
    idToObject.put(id, object);
    return id;
  }
Create an id of the given object.

@return the id generated for this object.
geode-core/src/main/java/org/apache/geode/internal/cache/persistence/CanonicalIdHolder.java