Hibernate version:
Hibernate 3
MySQL 5

I have configured the database to the isolation level serializable.

<property name="hibernate.connection.isolation">8</property>

In the method session.save() the program blocked and I got
an exception like

Lock wait timeout exceeded; try restarting transaction

Code Sample .
Transaction transaction1 = firstSession.beginTransaction();
testObject1.setCount(1);
firstSession.save(testObject1); <--- Problem

I have only one transaction open. Why blocked my transaction.

In all othe transaction isolation levels it works ?