JPA Exceptions

JPA exceptions are represented by a hierarchy of unchecked exceptions:

java.lang.Object
    java.lang.Throwable
        java.lang.Exception
            java.lang.RuntimeException
                javax.persistence.PersistenceException
                    javax.persistence.EntityExistsException
                    javax.persistence.EntityNotFoundException
                    javax.persistence.LockTimeoutException
                    javax.persistence.NonUniqueResultException
                    javax.persistence.NoResultException
                    javax.persistence.OptimisticLockException
                    javax.persistence.PessimisticLockException
                    javax.persistence.QueryTimeoutException
                    javax.persistence.RollbackException
                    javax.persistence.TransactionRequiredException

Exception Class Overview

The root of the JPA exception class subtree is:

• javax.persistence.PersistenceException

General errors are represented directly by the PersistenceException class. Some specific errors are represented by subclasses of PersistenceException. For example, an attempt to update the database with no active transaction is represented by:

• javax.persistence.TransactionRequiredException

Database update failures that require transaction rollback are represented by:

• javax.persistence.RollbackException

The RollbackException exception usually wraps the real failure cause as a nested exception  (which can be obtained by the getCause method) . For example, if a transaction fails because of an attempt to store a new entity object with a primary key that is already in use by another existing entity object, the nested exception is:

• javax.persistence.EntityExistsException

Other common causes for RollbackException are lock failures:

• javax.persistence.LockTimeoutException
• javax.persistence.OptimisticLockException
• javax.persistence.PessimisticLockException

Exceptions can also be thrown on an attempt to retrieve entity objects from the database. For example, when a required entity object is not found:

• javax.persistence.EntityNotFoundException

or during query execution:

• javax.persistence.NonUniqueResultException
• javax.persistence.NoResultException
• javax.persistence.QueryTimeoutException

The lock exceptions (above) may also be thrown during retrieval, if database lock has been requested for retrieved entity objects and it cannot be granted.