Hibernate Session and Transaction Management

Hibernate's auto-commit mode in transaction management is false by default.

There are patterns that are generally used in Hibernate Transaction management.

1) DB Transaction and Hibernate Session start and end simultaneously (session-per-request).

2) Chaining sessions and transactions with detached objects (session-per-request-with-detached-objects).

3) Multiple transaction management (session-per-conversation) connected to a session.

Transaction Demarcation with JTA

Hibernate uses JTA on J2EE/JEE application servers by default. Today, all J2EE/JEE application servers host JTA as built-in and any datasource used on these servers is automatically managed by JTATransactionManager.

The code below exemplifies this. The session-per-request pattern is obtained by connecting the current session to the transaction of the JTA.

Code Example 1:

embedded transaction-session management (built-in management)

try {
 UserTransaction tx = (UserTransaction)new InitialContext().lookup("java:comp/UserTransaction");

 tx.begin();

 factory.getCurrentSession().load(...); // hibernate session otomatik olarak açılır
 factory.getCurrentSession().persist(...);

 tx.commit(); // hibernate session otomatik olarak kapanır
}
catch (RuntimeException e) {
 tx.rollback(); // hibernate session otomatik olarak kapanır
 throw e;
}

Settings:

• set hibernate.transaction.manager_lookup_class to a lookup strategy for your JEE container
• set hibernate.transaction.factory_class to org.hibernate.transaction.JTATransactionFactory

Code Example 2:

Case where session management is done manually

UserTransaction tx = (UserTransaction)new InitialContext().lookup("java:comp/UserTransaction");

Session session = factory.openSession();

try {
 tx.begin();

 session.load(...);
 session.persist(...);

 session.flush();

 tx.commit();
}
catch (RuntimeException e) {
 tx.rollback();
 throw e;
}
finally {
 session.close();
}

Transaction Demarcation with JDBC

When JTA is not desired to be used, session-per-request pattern can be performed with Hibernate's Transactions without the need for JDBC API as follows:

Code Example 3:

try {
 // proxied session otomatik olarak açılır ve current Java thread'e bağlanır.
 factory.getCurrentSession().beginTransaction(); 
  
 factory.getCurrentSession().load(...);
 factory.getCurrentSession().persist(...);
 factory.getCurrentSession().getTransaction().commit();
}
catch (RuntimeException e) {
 factory.getCurrentSession().getTransaction().rollback();
 throw e; 
}

Hibernare cannot automatically connect current session to transaction like JTA, instead it connects current java thread in proxied state state.

This thread-bound strategy works in all JSE applications. In JEE applications, it is better to use JTA's transaction-bound strategy, and even in JSE applications, JTA can be used after installing it.

The following settings are required to use the thread-bound strategy.

Settings:

• set hibernate.transaction.factory_class to org.hibernate.transaction.JDBCTransactionFactory
• set hibernate.current_session_context_class to thread

Transaction Demarcation with EJB/CMT

It is possible to configure using only annotation. Transaction is opened automatically and if there is no error in the method, it is committed, in case of error, rollback is made.

@TransactionAttribute(TransactionAttributeType.REQUIRED)  
public void doSomeWork() {  
  factory.getCurrentSession().load(...);  
  factory.getCurrentSession().persist(...);  
}  

In EJB2x only xml conf. There was, however, it is possible to manage transactions in a declarative manner with annotations in EJB3x.

Settings:

• set hibernate.transaction.manager_lookup_class to a lookup strategy for your JEE container
• set hibernate.transaction.factory_class to org.hibernate.transaction.CMTTransactionFactory

Transaction Demarcation with Interceptor

It is possible to completely remove transaction codes from within the data access code. For this, a filter (open session in view pattern) or AOP interceptor running on each request is sufficient.