Repository Spring

The use of @JPARepository or @CrudRepository is very handy, developers can do basic operations with no SQL operations. However it also hide the transaccion managemetn. By default every method has a transacciton scope. I have seen so many developers forget the use of @Transactional scope in their services. Hibernate and JPA force to you to create a Transaccion but with the use of frameworks it is deep hide and frecuantly ommited, skipped or simplely unknown by mediocre developers

Behaviour without Transaction management

the service produces different output depending of use of Transaccional scope

    @Transactional
    public void getGetOlder(int age, int plus) {

        List<User> listUsers = repoUser.findByAgeGreaterThan(age);
        for (User user : listUsers) {
            user.setAge(user.getAge() + plus);
            repoUser.save(user);
        }
    }

This give you a log with only one transaccion

2019-08-06 11:42:19,731 DEBUG [main] o.h.e.t.i.TransactionImpl [TransactionImpl.java:101] committing
2019-08-06 11:42:19,731 DEBUG [main] o.h.e.i.AbstractFlushingEventListener [AbstractFlushingEventListener.java:141] Processing flush-time cascades
2019-08-06 11:42:19,731 DEBUG [main] o.h.e.i.AbstractFlushingEventListener [AbstractFlushingEventListener.java:193] Dirty checking collections
2019-08-06 11:42:19,733 DEBUG [main] o.h.e.i.AbstractFlushingEventListener [AbstractFlushingEventListener.java:115] Flushed: 0 insertions, 2 updates, 0 deletions to 2 objects
2019-08-06 11:42:19,733 DEBUG [main] o.h.e.i.AbstractFlushingEventListener [AbstractFlushingEventListener.java:122] Flushed: 0 (re)creations, 0 updates, 0 removals to 0 collections
2019-08-06 11:42:19,734 DEBUG [main] o.h.i.u.EntityPrinter [EntityPrinter.java:110] Listing entities:
2019-08-06 11:42:19,734 DEBUG [main] o.h.i.u.EntityPrinter [EntityPrinter.java:117] org.jordi.h2db.springboot.models.User{firstName=Joana, lastName=Fernandez, id=2, age=11}
2019-08-06 11:42:19,734 DEBUG [main] o.h.i.u.EntityPrinter [EntityPrinter.java:117] org.jordi.h2db.springboot.models.User{firstName=Rachel, lastName=Fernandez, id=1, age=11}
2019-08-06 11:42:19,735 DEBUG [main] o.h.SQL [SqlStatementLogger.java:94] update users set age=?, first_name=?, last_name=? where id=?
2019-08-06 11:42:19,739 DEBUG [main] o.h.SQL [SqlStatementLogger.java:94] update users set age=?, first_name=?, last_name=? where id=?
2019-08-06 11:42:19,759 DEBUG [Thread-3] o.h.i.SessionFactoryImpl [SessionFactoryImpl.java:792] HHH000031: Closing

whereras if you ommit the transaccion you will the below where you can see two commits instead of one.:

2019-08-06 12:00:19,763 DEBUG [main] o.h.e.t.i.TransactionImpl [TransactionImpl.java:101] committing
2019-08-06 12:00:19,764 DEBUG [main] o.h.e.i.AbstractFlushingEventListener [AbstractFlushingEventListener.java:141] Processing flush-time cascades
2019-08-06 12:00:19,765 DEBUG [main] o.h.e.i.AbstractFlushingEventListener [AbstractFlushingEventListener.java:193] Dirty checking collections
2019-08-06 12:00:19,766 DEBUG [main] o.h.e.i.AbstractFlushingEventListener [AbstractFlushingEventListener.java:115] Flushed: 0 insertions, 1 updates, 0 deletions to 1 objects
2019-08-06 12:00:19,767 DEBUG [main] o.h.e.i.AbstractFlushingEventListener [AbstractFlushingEventListener.java:122] Flushed: 0 (re)creations, 0 updates, 0 removals to 0 collections
2019-08-06 12:00:19,767 DEBUG [main] o.h.i.u.EntityPrinter [EntityPrinter.java:110] Listing entities:
2019-08-06 12:00:19,768 DEBUG [main] o.h.i.u.EntityPrinter [EntityPrinter.java:117] org.jordi.h2db.springboot.models.User{firstName=Rachel, lastName=Fernandez, id=1, age=11}
2019-08-06 12:00:19,769 DEBUG [main] o.h.SQL [SqlStatementLogger.java:94] update users set age=?, first_name=?, last_name=? where id=?
2019-08-06 12:00:19,774 DEBUG [main] o.h.e.t.i.TransactionImpl [TransactionImpl.java:56] On TransactionImpl creation, JpaCompliance#isJpaTransactionComplianceEnabled == false
2019-08-06 12:00:19,775 DEBUG [main] o.h.e.t.i.TransactionImpl [TransactionImpl.java:84] begin
2019-08-06 12:00:19,776 DEBUG [main] o.h.l.Loader [Loader.java:2269] Loading entity: [org.jordi.h2db.springboot.models.User#2]
2019-08-06 12:00:19,777 DEBUG [main] o.h.SQL [SqlStatementLogger.java:94] select user0_.id as id1_0_0_, user0_.age as age2_0_0_, user0_.first_name as first_na3_0_0_, user0_.last_name as last_nam4_0_0_ from users user0_ where user0_.id=?
2019-08-06 12:00:19,780 DEBUG [main] o.h.l.Loader [DelegatingBasicLogger.java:384] Result set row: 0
2019-08-06 12:00:19,781 DEBUG [main] o.h.l.Loader [Loader.java:1532] Result row: EntityKey[org.jordi.h2db.springboot.models.User#2]
2019-08-06 12:00:19,784 DEBUG [main] o.h.e.i.TwoPhaseLoad [TwoPhaseLoad.java:145] Resolving associations for [org.jordi.h2db.springboot.models.User#2]
2019-08-06 12:00:19,785 DEBUG [main] o.h.e.i.TwoPhaseLoad [TwoPhaseLoad.java:290] Done materializing entity [org.jordi.h2db.springboot.models.User#2]
2019-08-06 12:00:19,785 DEBUG [main] o.h.l.Loader [Loader.java:2298] Done entity load
2019-08-06 12:00:19,786 DEBUG [main] o.h.e.t.i.TransactionImpl [TransactionImpl.java:101] committing
2019-08-06 12:00:19,787 DEBUG [main] o.h.e.i.AbstractFlushingEventListener [AbstractFlushingEventListener.java:141] Processing flush-time cascades
2019-08-06 12:00:19,787 DEBUG [main] o.h.e.i.AbstractFlushingEventListener [AbstractFlushingEventListener.java:193] Dirty checking collections
2019-08-06 12:00:19,788 DEBUG [main] o.h.e.i.AbstractFlushingEventListener [AbstractFlushingEventListener.java:115] Flushed: 0 insertions, 1 updates, 0 deletions to 1 objects
2019-08-06 12:00:19,789 DEBUG [main] o.h.e.i.AbstractFlushingEventListener [AbstractFlushingEventListener.java:122] Flushed: 0 (re)creations, 0 updates, 0 removals to 0 collections
2019-08-06 12:00:19,789 DEBUG [main] o.h.i.u.EntityPrinter [EntityPrinter.java:110] Listing entities:
2019-08-06 12:00:19,790 DEBUG [main] o.h.i.u.EntityPrinter [EntityPrinter.java:117] org.jordi.h2db.springboot.models.User{firstName=Joana, lastName=Fernandez, id=2, age=11}
2019-08-06 12:00:19,790 DEBUG [main] o.h.SQL [SqlStatementLogger.java:94] update users set age=?, first_name=?, last_name=? where id=?
2019-08-06 12:00:19,810 DEBUG [Thread-3] o.h.i.SessionFactoryImpl [SessionFactoryImpl.java:792] HHH000031: Closing