When attempting to insert a row an Exception occurs:
"javax.persistence.PersistenceException: org.hibernate.PropertyAccessException: IllegalArgumentException occurred while calling setter"

The table has a compound primary key and one of the key parts is an identity (Yes, this is bad).

The insert seems to complete but after the insert the Basic Property setter is invoked on the Primary Key identity part but instead of having the ID it has a place holder value. The placeholder is not of the same type (Integer) and thus the IllegalArgumentException is thrown.