Object [id=xxx] was not of the specified subclass

Symptom:

2018-10-29 20:06:57,680 ERROR [main] [ch.algotrader.starter.ServerStarter] Object [id=205] was not of the specified subclass [ch.algotrader.entity.SubscriptionImpl] : loaded object was of wrong class class ch.algotrader.entity.PositionImpl 
org.hibernate.WrongClassException: Object [id=205] was not of the specified subclass [ch.algotrader.entity.SubscriptionImpl] : loaded object was of wrong class class ch.algotrader.entity.PositionImpl

Because PropertyHolders use Hibernate Union-Subclass strategy, Id's of different PropertyHolder tables may not overlap. When Entities are saved through AlgoTrader unique Id's will be enforced by Hibernate. But when saving rows in the database directly (within the tables strategy, position, subscription or order_preference) one has to manually ensure there are no overlapping Ids.

The following SQL script can be used to check whether a certain Id is already in use:

select id from strategy
union select id from position
union select id from subscription
union select id from order_preference;