Héllo, I have some troubles getting hibernate 3.5 working properly with HSQLDB (in process mode), I got same issues with SQLite [1] but everything works as excepted with mysql. I'm new to hibernate and all this java art so forgive me if I make big errors. The problem is each time I start my app which creates and populates serveral table, the next run the db seems empty, and I have to fill it again. I've setup a project using the 3.5 version of hibernate using JPA/EJB. I've setup a persistence unit (thanks to netbeans) automatically generating the presistence.xml needed for the emf setup persistence.xml <code> <?xml version="1.0" encoding="UTF-8"?> <persistence version="1.0" xmlns="http://java.sun.com/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation=" http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_1_0.xsd"> <persistence-unit name="PMMPU2" transaction-type="RESOURCE_LOCAL"> <provider>org.hibernate.ejb.HibernatePersistence</provider> <class>model.Extrait</class> <class>model.Mot</class> <class>model.Prefixe</class> <class>model.Suffixe</class> <class>model.Texte</class> <properties> <property name="hibernate.connection.username" value="SA"/> <property name="hibernate.connection.driver_class" value="org.hsqldb.jdbcDriver"/> <property name="hibernate.connection.password" value=""/> <property name="hibernate.connection.url" value="jdbc:hsqldb:file:db/base;shutdown=true"/> <property name="hibernate.cache.provider_class" value="org.hibernate.cache.NoCacheProvider"/> <property name="hibernate.hbm2ddl.auto" value="update"/> </properties> </persistence-unit> </persistence> </code> http://java.pastebin.com/LFfB0gSt I have also a HibernateUtil which helps me with emf & em: <code> public class HibernateUtil { private static EntityManagerFactory emf = null; private static EntityManager em = null; public static EntityManagerFactory getEmf() { if(emf == null) { Map<String, Object> configOverrides = new HashMap<String, Object>(); // configOverrides.put("hibernate.hbm2ddl.auto", "update"); configOverrides.put("hibernate.show_sql", "true"); emf = Persistence.createEntityManagerFactory("PMMPU2", configOverrides); } return emf; } public static EntityManager getEm() { if(em == null) em = getEmf().createEntityManager(); return em; } } </code> http://java.pastebin.com/kvyxruH0 1) As you can see I overdrive some settings getEMF. 2) How should a use EM instances; one for all the app, is that different on desktop & web ? 3) How could I change HSQLDB options with hibernate to use CACHED tables by default ? [1] sqliteJDBC http://www.zentus.com/sqlitejdbc/ + hibernate-sqlite http://code.google.com/p/hibernate-sqlite/