CODEWITHSUNDEEP
javahibernatespringspring-transactions
Jim
Jim

Reputation: 11

Synchronizing spring transaction

We use Spring and Hibernate in our project and has a layered Architechture. Controller -> Service -> Manager -> Dao. Transactions start in the Manager layer. A method in the service layer which updates an object in the db is called by many threads and this is causing to throw a stale object expection. So I made this method Synchronized and still see the stale object exception thrown. What am I doing wrong here? Any better way to handle this case?

Thanks for the help in advance.

Upvotes: 1

Views: 1793

Answers (2)

JB Nizet
JB Nizet

Reputation: 691725

The stale object exception is thrown when an entity has been modified between the time it was read and the time it's updated. This can happen inside a single transaction, but may also happen when you read an object in a transaction, modify it (in the controller layer, for example), then start another transaction and merge/update it (in this case, minutes or hours can separate the read and the update).

The exception is thrown to help you avoid conflicts between users.

If you don't care about conflicts (i.e. the last update always wins and replaces what the previous ones have written), then don't use optimistic locking. If you're concerned about conflicts, then StaleObjectExceptions will happen, and you should popup a meaningful message to the end user, asking him to reload the data and try to modify it again. There's no way to avoid them. You must just be optimistic and hope that they won't happen often.

Note that your synchronized trick will work only if

  • the exception happens only when reading and writing in the same transaction
  • updates to the entity are only made by this service
  • your application is not clustered.

It might also reduce the throughput dramatically, because you forbid any concurrent updates, regardless of which entities are updated by the concurrent transactions. It's like if you locked the whole table for the duration of the whole transaction.

Upvotes: 4

Sean Patrick Floyd
Sean Patrick Floyd

Reputation: 298898

My guess is that you would need to configure optimistic locking on the Hibernate side.

Upvotes: 1

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