advance java in java notes

Persistent objects and collections are short lived single threaded objects, which store the persistent state. These objects  synchronize their state with the database depending on your flush strategy (i.e. auto-flush where as soon as setXXX() method is called or an item is removed from a Set, List  etc or define your own synchronization points with … Read more

Session is a light weight and a non-threadsafe object (No, you cannot share it between threads) that represents a single unit-of-work with the database. Sessions are opened by a SessionFactory and then are closed when all work is complete. Session is the primary interface for the persistence service. A session obtains a database connection lazily … Read more

SessionFactory is Hibernate’s concept of a single datastore and is threadsafe so that many threads can access it concurrently and request for sessions and immutable cache of compiled mappings for a single database. A SessionFactory is usually only built once at startup. SessionFactory should be wrapped in some kind of singleton so that it can … Read more

The configuration files hibernate.cfg.xml (or hibernate.properties) and mapping files *.hbm.xml are used by the Configuration class to create (i.e. configure and bootstraphibernate) the SessionFactory, which in turn creates the Session instances. Session instances are the primary interface for the persistence service.hibernate.cfg.xml (alternatively can use hibernate.properties): These two files are used to configure the hibernate sevice … Read more