I wish to know what exceptions are thrown (Hibernate JPA spec) for some common situations listed below.

1. Database Constraints are violated when inserting or updating Entity (including unique constraints and foreign key constraints).
2. Searching for an entity but entity does not exist in the database or a NamedQuery returns no records
3. Entity has been read in memory and detached, another user edits and commits the same entity. The detached entity is merged back and tried to persist.

regards,
Nirvan