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Should session and factory be closed?

I'm using Hibernate 5.0.2.Final with a Data-Source connection (On a Tomcat 8.0.15) and started to ask myself if it's necessary to not only close the Session but also the SessionFactory?
Right now it looks like this:
public static List<HibernateList> getHibernateList() {
Session session = null;
final String hql = "SELECT H FROM myhibernate.MyHibernate";
try {
SessionFactory factory = HibernateUtil.getSessionFactory();
session = factory.openSession();
session.beginTransaction();
Query query = session.createQuery(hql);
return query.list();
} catch (HibernateException hibex) {
Logger.getLogger(Hibernatepicker.class.getName()).log(Level.INFO, null, hql);
Logger.getLogger(Hibernatepicker.class.getName()).log(Level.SEVERE, null, hibex);
} finally {
try {
if (session != null) {
session.close();
}
} catch (HibernateException hibex) {
}//Nothing I could do...
}
return null;
}
Some details from the hibernate.cfg.xml
<property name="hibernate.connection.datasource">java:comp/env/jdbc/sqlserv</property>
<property name="current_session_context_class">thread</property>
<property name="cache.provider_class">org.hibernate.cache.NoCacheProvider</property>
<property name="hbm2ddl.auto">auto</property>
<property name="show_sql">false</property>
<property name="hibernate.generate_statistics">true</property>
And the HibernateUtil:
public class HibernateUtil {
private static final SessionFactory sessionFactory;
static {
try {
Configuration cfg = new Configuration();
sessionFactory = cfg.configure("hibernate.cfg.xml").buildSessionFactory();
} catch (Throwable ex) {
Logger.getLogger(HibernateUtil.class.getName()).log(Level.SEVERE, null, ex);
throw new ExceptionInInitializerError(ex);
}
}
public static SessionFactory getSessionFactory() {
return sessionFactory;
}
}
I'm undecided whether it's necessary or not to call this method in the finally-block instead of only closing the session:
public static void disconnect(Session session, SessionFactory factory) {
try {
if (session != null) {
session.close();
} else {
Logger.getLogger(HibernateUtil.class.getName()).log(Level.INFO, null, "Session is Null");
}
} catch (HibernateException | NullPointerException hibex) {
Logger.getLogger(HibernateUtil.class.getName()).log(Level.INFO, null, "Couldn't close session, but there's nothing we can do...");
Logger.getLogger(HibernateUtil.class.getName()).log(Level.SEVERE, null, hibex);
}
try {
if (factory != null) {
factory.close();
} else {
Logger.getLogger(HibernateUtil.class.getName()).log(Level.INFO, null, "Factory is Null");
}
} catch (HibernateException | NullPointerException hibex) {
Logger.getLogger(HibernateUtil.class.getName()).log(Level.INFO, null, "Couldn't close session, but there's nothing we can do...");
Logger.getLogger(HibernateUtil.class.getName()).log(Level.SEVERE, null, hibex);
}
}

You should not close your SessionFactory on every query. Your SessionFactory should be initialised only once per application.
From the hibernate documentation.
The main contract here is the creation of Session instances. Usually
an application has a single SessionFactory instance and threads
servicing client requests obtain Session instances from this factory.
The internal state of a SessionFactory is immutable. Once it is
created this internal state is set. This internal state includes all
of the metadata about Object/Relational Mapping.
Implementors must be threadsafe.

Shorter version of Hibernate query

I have hibernate query, for example get user by id:
public User findById(int id){
SessionFactory sf = HibernateUtil.getSessionFactory();
Session session = sf.openSession();
Transaction tx = null;
User user = null;
try{
tx = session.beginTransaction();
user = (User) session.get(User.class, id);
session.getTransaction().commit();
} catch(HibernateException e){
if(null != tx) tx.rollback();
System.out.println("HibernateException, transaction will be rollbacked");
} catch(Exception e){
e.printStackTrace();
}
finally {
session.close();
}
return user;
}
It's ok for one query, but i need dublicate all of this code to every query.
I need just on single code:
user = (User) session.get(User.class, id);
Is it possible to put other code to another class, method or something else?
Updated
HibernateUtil:
public class HibernateUtil {
private static final SessionFactory sessionFactory = buildSessionFactory();
private static SessionFactory buildSessionFactory() {
try {
// Create the SessionFactory from hibernate.cfg.xml
return new AnnotationConfiguration().configure()
.buildSessionFactory();
} catch (Throwable ex) {
System.err.println("Initial SessionFactory creation failed." + ex);
throw new ExceptionInInitializerError(ex);
}
}
public static SessionFactory getSessionFactory() {
return sessionFactory;
}
}

It is a good practice to keep one Hibernate utility class which will have a static method to provide us the hibernate session. Moreover you can reuse the hibernate session by preventing making a new session on each query by using some simple logic.

Proper use of session(hibernate)

Sorry for my english. I learn JavaEE and i dont know proper or not i use session in hibernate. How to use them? I use pattern DAO and hibernate. Tell my how property use session
this is HibernateUtil class
private static final SessionFactory sessionFactory;
static {
try{
sessionFactory = new Configuration().configure("/app/web/landingpage/HibernateConnect/hibernate.cfg.xml").buildSessionFactory();
}catch(Throwable ex) {
System.out.println("Error " + ex);
throw new ExceptionInInitializerError(ex);
}
}
public static SessionFactory getSessionFactory() {
return sessionFactory;
}
public static void close(Session session) {
if (session != null) {
try {
session.close();
} catch (HibernateException ignored) {
System.out.print("Couldn't close Session" + ignored);
}
}
}
And that class makes all operation db CategoryDaoImpl
public class CategoryDaoImpl implements CategoryDao{
private Session session = null;
//get all category
public Collection getAllCategory() {
List categoris = new ArrayList<Category>();
try{
session = HibernateUtil.getSessionFactory().openSession();
categoris = session.createCriteria(Category.class).list();
}catch(Exception e) {
System.out.println("getAllCategory "+ e);
}finally{
if(session != null && session.isOpen())
session.close();
}
return categoris;
}
//get category id
public Category getCategory(int id) {
Category cat = null;
try {
session = HibernateUtil.getSessionFactory().openSession();
cat = (Category) session.load(Category.class, id);
}catch(Exception e) {
System.out.println("getAllCategory "+ e);
}finally{
if(session != null && session.isOpen())
session.close();
}
return cat;
}
//and below few methods that use it the some way session
}
and this servlet take results indexuser
Session session = HibernateUtil.getSessionFactory().getCurrentSession();
session.beginTransaction();
try{
Collection allcategory = Factory.getInstance().getCatDAO().getAllCategory();
request.setAttribute("allcategory", allcategory);
request.getRequestDispatcher("/index.jsp").forward(request, response);
} catch(Exception e) {
System.out.println(e);
} finally{
if(session!=null && session.isOpen())
session.close();
}

The main contract here is the creation of Session instances. Usually an application has a single SessionFactory instance and threads servicing client requests obtain Session instances from this factory.
The internal state of a SessionFactory is immutable. Once it is created this internal state is set. This internal state includes all of the metadata about Object/Relational Mapping.
Basically session is used to get physical connection with database. So while you performing any DB Operations it will first open Session using sessionFactory and then Session do physical connection with database and then perform your operation and after performing operation you can close it.
Session is light weight.

java hibernate tomcat configuration - Session will not be opened

I am trying to configure hibernate and tomcat, so that tomcat will manage the database conections, but I am getting some errors.
Could you help? Here is my code:
Here is the HibernateUtil
public class HibernateUtil {
private static final SessionFactory sessionFactory = buildSessionFactory();
private static SessionFactory buildSessionFactory() {
try {
// Create the SessionFactory from hibernate.cfg.xml
return new AnnotationConfiguration().configure().buildSessionFactory();
} catch (Throwable ex) {
// Make sure you log the exception, as it might be swallowed
System.err.println("Initial SessionFactory creation failed." + ex);
throw new ExceptionInInitializerError(ex);
}
}
public static SessionFactory getSessionFactory() {
return sessionFactory;
}
public static void shutdown() {
// Close caches and connection pools
getSessionFactory().close();
}
}
HibernateListener:
public class HibernateListener implements ServletContextListener {
/* public void contextInitialized(ServletContextEvent event) {
HibernateUtil.getSessionFactory(); // Just call the static initializer
// of that class
}
public void contextDestroyed(ServletContextEvent event) {
HibernateUtil.getSessionFactory().close(); // Free all resources
}
}*/
#Override
public void contextInitialized(ServletContextEvent arg0) {
System.out.println("\n\tInside contextInitialized()\n")
Session session = HibernateUtil.getSessionFactory().openSession();
session.beginTransaction();
}
#Override
public void contextDestroyed(ServletContextEvent arg0) {
HibernateUtil.shutdown();
}
}
I have also made an entry in web.xml
<listener>
<listener-class>hibernate.HibernateListener</listener-class>
</listener>
I have created a jsp file and try to run a piece of code, which is:
public Employee getEmployeeByLogin(String login){
Employee p= null;
Session session = HibernateUtil.getSessionFactory().getCurrentSession();
Query query = session.createQuery("from employee p where p.login = '" + login +"'");
p = (Employee) query.uniqueResult();
return p;
}
The error I am getting is:
org.apache.jasper.JasperException: org.hibernate.HibernateException: createQuery is not valid without active transaction
I tried to do it similar way as described in https://community.jboss.org/wiki/UsingHibernateWithTomcat# but without success....
So once again. Please help.

HibernateSessionFactory class doesn't change data from database

In our application we have an HibernateSessionFactory class, that is opening and closing connections. Everything is okay, but when we are updating data in the database, it doesn't change in our application. Unfortunately, we see old data from the database. How can I fix this?
public class HibernateSessionFactory {
private static final ThreadLocal threadLocal = new ThreadLocal();
private static org.hibernate.SessionFactory sessionFactory;
private static Configuration configuration = new Configuration();
private static ServiceRegistry serviceRegistry;
private static final Logger log = Logger.getLogger(
HibernateSessionFactory.class);
static {
try {
configuration.configure();
serviceRegistry = new ServiceRegistryBuilder()
.applySettings(configuration.getProperties())
.buildServiceRegistry();
sessionFactory = configuration.buildSessionFactory(serviceRegistry);
} catch (Exception e) {
log.error("Error Creating SessionFactory", e);
}
}
private HibernateSessionFactory() {}
public static Session getSession() throws HibernateException {
Session session = (Session) threadLocal.get();
if (session == null || !session.isOpen()) {
if (sessionFactory == null) {
rebuildSessionFactory();
}
session = (sessionFactory != null) ?
sessionFactory.openSession() : null;
threadLocal.set(session);
}
return session;
}
public static void rebuildSessionFactory() {
try {
configuration.configure();
serviceRegistry = new ServiceRegistryBuilder()
.applySettings(configuration.getProperties())
.buildServiceRegistry();
sessionFactory = configuration.buildSessionFactory(serviceRegistry);
} catch (Exception e) {
log.error("Error Creating SessionFactory", e);
}
}
public static void closeSession() throws HibernateException {
Session session = (Session) threadLocal.get();
threadLocal.set(null);
if (session != null) {
session.flush();
session.close();
}
}
public static org.hibernate.SessionFactory getSessionFactory() {
return sessionFactory;
}
public static Configuration getConfiguration() {
return configuration;
}
}
.
#SuppressWarnings("unchecked")
public List<Tauthor> getAuthors() throws HibernateException {
log.debug("getting all authors");
Query queryObject = null;
List<Tauthor> authors = null;
Session session = HibernateSessionFactory.getSession();
try {
String queryString = "from Tauthor";
queryObject = session.createQuery(queryString);
authors = queryObject.list();
} catch (HibernateException e) {
log.error("get all authors failed", e);
throw e;
} finally {
HibernateSessionFactory.closeSession();
}
return authors;
}

You haven't shared your code where you write data to the database. Without that, I can think of only a few reasons as to why your data output is old instead of new data:
Your transactions are not being committed.
Hibernate hasn't written to the database at the time of data queried by you.
Hibernate's cache hasn't been updated, which results in query returning old data.
You should verify that data has been written to the Database with a db developer tool and try disabling all hibernate caching to see if the result changes.