How do synchronized static methods work in Java and can I use it for loading Hibernate entities?
concurrency, hibernate, java, multithreading, synchronization
Solution
By using synchronized on a static method lock you will synchronize the class methods and attributes ( as opposed to instance methods and attributes )
So your assumption is correct.
I am wondering if making the method synchronized is the right approach to ensure thread-safety.
Not really. You should let your RDBMS do that work instead. They are good at this kind of stuff.
The only thing you will get by synchronizing the access to the database is to make your application terribly slow. Further more, in the code you posted you're building a Session Factory each time, that way, your application will spend more time accessing the DB than performing the actual job.
Imagine the following scenario:
Client A and B attempt to insert different information into record X of table T.
With your approach the only thing you're getting is to make sure one is called after the other, when this would happen anyway in the DB, because the RDBMS will prevent them from inserting half information from A and half from B at the same time. The result will be the same but only 5 times ( or more ) slower.
Probably it could be better to take a look at the "Transactions and Concurrency" chapter in the Hibernate documentation. Most of the times the problems you're trying to solve, have been solved already and a much better way.
Problem
If I have a util class with static methods that will call Hibernate functions to accomplish basic data access. I am wondering if making the method `synchronized` is the right approach to ensure thread-safety. I want this to prevent access of info to the same DB instance. However, I'm now sure if the following code are preventing `getObjectById` being called for all Classes when it is called by a particular class. ``` public class Utils { public static synchronized Object getObjectById (Class objclass, Long id) { // call hibernate class Session session = new Configuration().configure().buildSessionFactory().openSession(); Object obj = session.load(objclass, id); session.close(); return obj; } // other static methods } ```