Doc: `JdbcTransactionManager` vs `DataSourceTransactionManager`

[manueljordan]

Through the javadoc of PlatformTransactionManager I did realize about the JdbcTransactionManager class. The latter is a subclass of DataSourceTransactionManager.

Normally and practically always the DataSourceTransactionManager class is used to define the TX infrastructure for JDBC and MyBatis.

Now, to be honest, is not clear in the javadoc of the JdbcTransactionManager class when it is mandatory over DataSourceTransactionManager or what is/are the advantages over its superclass.

I read all the sections of the Transaction Management section of the Reference documentation and the JdbcTransactionManager term does not appear.

Therefore is not clear with the current documentation when is mandatory use JdbcTransactionManager .

Thanks for your understanding.

[jhoeller]

The only difference is exception translation: Like with JpaTransactionManager, there is DataAccessException translation on commit here. Where DataSourceTransactionManager will only ever throw TransactionSystemException on commit, JdbcTransactionManager is more sophisticated and translates locking failures etc to corresponding DataAccessException subclasses. Note that calling code needs to be prepared for that, not exclusively expecting TransactionSystemException in such scenarios. That's the main reason why those are two separate transaction manager classes to choose from.

It is effectively never mandatory to use JdbcTransactionManager. That said, it is a good idea to use it in application setups that are used to JPA-style exception translation (e.g. having pluggable repository implementations with JPA and JDBC variants). It is also a good idea to use it with callers that are able to handle specific DataAccessException subclasses in catch blocks around transactions, providing clearer and more expressive exceptions for concurrency failures (e.g. with PostgreSQL). I'll make sure to mention this in the reference documentation, generally recommending it over DataSourceTransactionManager these days.