If you enabled read-only second-level cache in Hibernate and have the following error:

Stack Trace:

* org.hibernate.cache.ReadOnlyCache.lock(ReadOnlyCache.java:43)
* org.hibernate.action.EntityUpdateAction.execute(EntityUpdateAction.java:69)
* org.hibernate.engine.ActionQueue.execute(ActionQueue.java:239)
* org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:223)
* org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:137)
* org.hibernate.event.def.AbstractFlushingEventListener.performExecutions(AbstractFlushingEventListener.java:274)
* org.hibernate.event.def.DefaultFlushEventListener.onFlushefaultFlushEventListener.java:27)
* org.hibernate.impl.SessionImpl.flush(SessionImpl.java:730)
[...]