Why use @Transactional Jboss Seam

Question

I'm trying to understand why i need use @Transactional in some cases, let's see.

If i use this method without @Transactional annotation the jboss return on log: "Close the connection yourself. Closing connection for you".

public void doSomething() {

        ((Session) em.getDelegate()).doWork(new Work() {
            @Transactional(TransactionPropagationType.NEVER)
            public void execute(Connection connection) throws SQLException {
                StringBuilder sqlSP = new StringBuilder();
                sqlSP.append("{ call ");
                sqlSP.append("myprocedure");
                sqlSP.append("(?)}");

                connection.setReadOnly(true);
                CallableStatement cs = connection.prepareCall(sqlSP.toString());

                cs.setInt(1, 1020);             
                cs.execute();

                //FORCE A EXCEPTION and JBOSS SHOW "Closing connection for you"
                throw new MyException("FATAL ERROR");
            }
        });
    }

But when i put "@Transactional" the problem disappear, i don't understand why. Someone can explain ?

Answer 1

Standard way of handling DB calls is to : 1. open connection 2. open session and/or transaction 3. do stuff 4. close transaction and/or seasion 5. close connection

That's basicly what that annotation do for You ;) I strongly suggest to learn more about dealling with those kind of things.