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Spring #transactional with hibernate issue - not valid without an active transaction

Preamble - using Spring
I am confused as to the purpose of the spring #Transactional annotation. I thought from a few blog posts I've read that it would allow me to simplify transaction management and just write this, and it would handle connection/commit/rollback automagically:
public class DaoImpl implements Dao {
#Autowired
private SessionFactory sessionFactory;
#Transactional
public void saveOrUpdateOne(final AdditionalDataItem item) {
Session session = sessionFactory.getCurrentSession();
session.saveOrUpdate(p_item);
}
}
However this gives me an exception: " Calling method 'saveOrUpdate' is not valid without an active transaction"
If I instead change the save method to this, it all works - so my question is, what is #Transactional doing?
#Override
#Transactional
public void saveOrUpdateOne(final AdditionalDataItem p_item) {
Session session = null;
Transaction trans = null;
try {
session = sessionFactory.getCurrentSession();
trans = session.beginTransaction();
TransactionStatus status = trans.getStatus();
session.saveOrUpdate(p_item);
trans.commit();
} catch (Exception e) {
LOGGER.error("Exception saving data: {}", e.getMessage());
if (trans != null) {
try {
trans.rollback();
} catch (RuntimeException rbe) {
LOGGER.error("Couldn’t roll back transaction", rbe);
}
}
} finally {
if (session != null && session.isOpen()) {
try {
session.close();
} catch (HibernateException ne) {
LOGGER.error("Couldn’t close session", ne);
}
}
}
}
For reference, I'm using Java 11 with Spring Framework 5.3.7 and hibernate 5.5.7 and have appropriate dao, session factory and tx manager beans:
<bean id="sessionFactory"
class="org.springframework.orm.hibernate5.LocalSessionFactoryBean">
<property name="dataSource" ref="${sessionFactory.datasource}" />
<property name="configLocation" value="${sessionFactory.configLocation}" />
</bean>
<bean id="txManager"
class="org.springframework.orm.hibernate5.HibernateTransactionManager">
<property name="sessionFactory" ref="sessionFactory"/>
</bean>
<bean id="Dao" class="com.xxxxx.dao.DaoImpl">
<property name="sessionFactory" ref="sessionFactory" />
</bean>

It is because you do not enable #Transactional yet and also not begin the transaction when calling session.saveOrUpdate(), so it gives you the error 'not valid without an active transaction' .
To enable #Transactional, you have to use #EnableTransactionManagement or add <tx:annotation-driven/> in case you are using XML configuration . It basically does the following for you (source) :
#EnableTransactionManagement and <tx:annotation-driven/> are
responsible for registering the necessary Spring components that power
annotation-driven transaction management, such as the
TransactionInterceptor and the proxy- or AspectJ-based advice that
weaves the interceptor into the call stack when JdbcFooRepository's
#Transactional methods are invoked.
Your working example works because you manually manage the transaction by yourself .It is nothing to do with #Transactional since you never enable it.
Take the working codes as an example , what #Transactional does for you is that you no longer need to manually write the following transaction codes as all of them will be encapsulated in the TransactionInterceptor and execute around your #Transactional method based on AOP :
public Object invoke() {
Session session = null;
Transaction trans = null;
try {
session = sessionFactory.getCurrentSession();
trans = session.beginTransaction();
TransactionStatus status = trans.getStatus();
/***********************************************/
Here it will invoke your #Transactional Method
/************************************************/
trans.commit();
} catch (Exception e) {
LOGGER.error("Exception saving data: {}", e.getMessage());
if (trans != null) {
try {
trans.rollback();
} catch (RuntimeException rbe) {
LOGGER.error("Couldn’t roll back transaction", rbe);
}
}
} finally {
if (session != null && session.isOpen()) {
try {
session.close();
} catch (HibernateException ne) {
LOGGER.error("Couldn’t close session", ne);
}
}
}
}
So you can see that your #Transactional method will become very clean after removing these "ceremony" codes.

#Transactional is used if you want to update 2 tables if one of them failed the other one will rollback automatic
you can use it above method
and you can call save or update using bean of a Repository class

Handling Hibernate Transactions

Currently I have this code duplicated in each one of my Controller methods:
Transaction transaction = HibernateUtil.getSessionFactory().getCurrentSession().getTransaction();
if (!HibernateUtil.getSessionFactory().getCurrentSession().getTransaction().isActive()) {
transaction.begin();
}
Is this the correct way or is there a better way of doing this, perhaps in a separate class that I can reference? If so, how? Every time I've tried to put it in a separate class and reference it from other classes, it failed.
edit: I'm trying to use as few external libraries as possible. I wouldn't use Hibernate if Java had an ORM/JPA implementation built into the JDK

I've run into this myself many times. Ordinarily my first recommendation would be Spring transaction management, however I understand you are trying to limit the number of third party libraries you are using.
Since you're using a static API in your HibernateUtil class, you may find it helpful to consolidate your logic in a method, and putting the 'what you want to do in a transaction' code (which varies controller to controller) in a callback.
First, define an interface to describe each controller's inTransaction behavior:
public interface TransactionCallback {
void doInTransaction();
}
Now, create a static method in your HibernateUtil class to handle beginning, committing, and if necessary rolling back your transactions:
public class HibernateUtil {
public static void inTransaction(TransactionCallback tc) {
Transaction transaction = HibernateUtil.getSessionFactory().getCurrentSession().getTransaction();
if (!HibernateUtil.getSessionFactory().getCurrentSession().getTransaction().isActive()) {
transaction.begin();
try {
tc.doInTransaction();
transaction.commit();
} catch (Exception e) {
transaction.rollback();
}
}
}
}
In your controller, you'd use your new method with an anonymous inner class:
....
HibernateUtil.inTransaction(new TransactionCallback() {
void doInTransaction() {
// do stuff for this controller
}
});
....
This approach should at least take care of the duplication you'd like to eliminate, and there's plenty of room for extending it to handle particular exceptions, etc.

You have to close hibernate transaction after each transaction (e.g. Controller request).
In this case you will not need
if (!HibernateUtil.getSessionFactory().getCurrentSession().getTransaction().isActive())
and you WILL need to call .close() each time after request.
It is better to use code like:
class Controller {
//...
commonActionMethod() {
begin transaction
specificActionMethod();
close transaction
}
And childs of this Controller class should implement specificActionMethod().
Code is clean. Transactions are safe. No third-party libs required.

You can Very well use JDK Proxies to implement your own AOP .
Ref : Link1 Link2
Have Service Layer to intract with DAO framework such as Hibernate and so. So that your controller is just controll the flow and your service can implement business.
Have SeviceLocator / FactoryPattern to get hold of your Service instances ( In other words return proxies instead of Actual instance).
Define your own Annotations and identify your methods required transaction or not. if required handle transaction around your method call in your proxy handler.
In this way you don't need to depend on any library other than JDK. and you can turn off or on transaction just by having Annotations.
If you start manage the instances ( services) you can lot of magics with combination of FactoryPattern + JDK Proxies ( Actual Interfaces) + AOP Concepts.

you can create separate class for connection.
public class HibernateUtil {
private static final SessionFactory sessionFactory = buildSessionFactory();
#SuppressWarnings("deprecation")
private static SessionFactory buildSessionFactory() {
try {
// Create the SessionFactory from Annotation
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;
}
}
On Server Side you can write :-
Session session=null;
Transaction tx=null;
try {
session =HibernateUtil.getSessionFactory().openSession();
tx=session.beginTransaction();
} catch (HibernateException e) {
e.printStackTrace();
}finally
{
session.close();
}

Avoiding the use of additional, external libraries, you may wish to supply an interceptor that implements that standard J2EE servlet Filter interface. Such implementation is sometimes referred to as the Open Session in View pattern. I cite the following from this page:
When an HTTP request has to be handled, a new Session and database transaction will begin. Right before the response is send to the client, and after all the work has been done, the transaction will be committed, and the Session will be closed.

If you are using spring in your project. I will suggest to use the TX using spring AOP, In that you just have to specify the pointcuts for your transactions. The Spring AOP TX will taken care of begin and commit the transaction on basis of your point cut and could also roll-back the TX in case of exception occurred. Please go through the link of example - here

package com.project.stackoverflow;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
public class HibernateUtil {
private static final ThreadLocal threadSession = new ThreadLocal();
private static SessionFactory sessionFactory;
/**
* A public method to get the Session.
*
* #return Session
*/
public static Session getSession() {
Session session = (Session) threadSession.get();
// Open a Session, if this thread has none yet
if ((null == session) || !session.isOpen()) {
logger.info("Null Session");
session = sessionFactory.openSession();
logger.info("Session Opened");
threadSession.set(session);
}
return session;
}
public static void closeSession() {
Session session = (Session) threadSession.get();
// Open a Session, if this thread has none yet
if (null != session) {
session.close();
session = null;
threadSession.set(null);
}
}
return sessionFactory;
}
public void setSessionFactory(SessionFactory sessionFactory) {
logger.info("Inside set session Factory");
this.sessionFactory = sessionFactory;
logger.info("After set session Factory");
}
public static void save(Object obj) {
getSession().save(obj);
getSession().flush();
}
public static void saveOrUpdate(Object obj) {
getSession().saveOrUpdate(obj);
getSession().flush();
}
public static void batchUpdate(Object obj) {
getSession().saveOrUpdate(obj);
getSession().flush();
}
public static void update(Object obj) {
getSession().update(obj);
getSession().flush();
}
public static void delete(Object obj) {
getSession().delete(obj);
getSession().flush();
}
}
You can probably go for this solution. I have made a separate JavaClass for Hibernate Instantiation and use. You can get the session from here itself which may suffice your need. Hope it helps :)

I used this technique.
My Servlet context is like this:
<beans:bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource"
destroy-method="close" p:driverClassName="${jdbc.driverClassName}"
p:url="${jdbc.databaseurl}" p:username="${jdbc.username}" p:password="${jdbc.password}" />
<beans:bean id="sessionFactory"
class="org.springframework.orm.hibernate3.LocalSessionFactoryBean">
<beans:property name="dataSource" ref="dataSource" />
<beans:property name="configLocation">
<beans:value>classpath:hibernate.cfg.xml</beans:value>
</beans:property>
<beans:property name="configurationClass">
<beans:value>org.hibernate.cfg.AnnotationConfiguration</beans:value>
</beans:property>
<beans:property name="hibernateProperties">
<beans:props>
<beans:prop key="hibernate.dialect">${jdbc.dialect}</beans:prop>
<beans:prop key="hibernate.show_sql">true</beans:prop>
</beans:props>
</beans:property>
</beans:bean>
<beans:bean id="transactionManager"
class="org.springframework.orm.hibernate3.HibernateTransactionManager">
<beans:property name="sessionFactory" ref="sessionFactory" />
</beans:bean>
<tx:annotation-driven transaction-manager="transactionManager" />
Then you can simply use
#Autowired
private SessionFactory sessionFactory;
Whenever I want to use a session or do any operations I simply do it like this:
Session session = sessionFactory.openSession();
Transaction transaction = session.beginTransaction();
session.save(userAccount);
transaction.commit();
session.close();
I think it will help.

If you have application server like glassfish, it has imbended eclipselink JPA/ORM implementation and you can manage transaction using standart JEE annotations.

JOOQ & transactions

I've been reading about transactions & jooq but I struggle to see how to implement it in practice.
Let's say I provide JOOQ with a custom ConnectionProvider which happens to use a connection pool with autocommit set to false.
The implementation is roughly:
#Override public Connection acquire() throws DataAccessException {
return pool.getConnection();
}
#Override public void release(Connection connection) throws DataAccessException {
connection.commit();
connection.close();
}
How would I go about wrapping two jooq queries into a single transaction?
It is easy with the DefaultConnectionProvider because there's only one connection - but with a pool I'm not sure how to go about it.

jOOQ 3.4 Transaction API
With jOOQ 3.4, a transaction API has been added to abstract over JDBC, Spring, or JTA transaction managers. This API can be used with Java 8 as such:
DSL.using(configuration)
.transaction(ctx -> {
DSL.using(ctx)
.update(TABLE)
.set(TABLE.COL, newValue)
.where(...)
.execute();
});
Or with pre-Java 8 syntax
DSL.using(configuration)
.transaction(new TransactionRunnable() {
#Override
public void run(Configuration ctx) {
DSL.using(ctx)
.update(TABLE)
.set(TABLE.COL, newValue)
.where(...)
.execute();
}
});
The idea is that the lambda expression (or anonymous class) form the transactional code, which:
Commits upon normal completion
Rolls back upon exception
The org.jooq.TransactionProvider SPI can be used to override the default behaviour, which implements nestable transactions via JDBC using Savepoints.
A Spring example
The current documentation shows an example when using Spring for transaction handling:
http://www.jooq.org/doc/latest/manual/getting-started/tutorials/jooq-with-spring/
This example essentially boils down to using a Spring TransactionAwareDataSourceProxy
<!-- Using Apache DBCP as a connection pooling library.
Replace this with your preferred DataSource implementation -->
<bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource"
init-method="createDataSource" destroy-method="close">
<property name="driverClassName" value="org.h2.Driver" />
<property name="url" value="jdbc:h2:~/maven-test" />
<property name="username" value="sa" />
<property name="password" value="" />
</bean>
<!-- Using Spring JDBC for transaction management -->
<bean id="transactionManager"
class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
<property name="dataSource" ref="dataSource" />
</bean>
<bean id="transactionAwareDataSource"
class="org.springframework.jdbc.datasource.TransactionAwareDataSourceProxy">
<constructor-arg ref="dataSource" />
</bean>
<!-- Bridging Spring JDBC data sources to jOOQ's ConnectionProvider -->
<bean class="org.jooq.impl.DataSourceConnectionProvider"
name="connectionProvider">
<constructor-arg ref="transactionAwareDataSource" />
</bean>
A running example is available from GitHub here:
https://github.com/jOOQ/jOOQ/tree/master/jOOQ-examples/jOOQ-spring-example
A Spring and Guice example
Although I personally wouldn't recommend it, some users have had success replacing a part of Spring's DI by Guice and handle transactions with Guice. There is also an integration-tested running example on GitHub for this use-case:
https://github.com/jOOQ/jOOQ/tree/master/jOOQ-examples/jOOQ-spring-guice-example

This is probably not the best way but it seems to work. The caveat is that it is not the release but the commit method which closes the connection and returns it to the pool, which is quite confusing and could lead to issues if some code "forgets" to commit...
So the client code looks like:
final PostgresConnectionProvider postgres =
new PostgresConnectionProvider("localhost", 5432, params.getDbName(), params.getUser(), params.getPass())
private static DSLContext sql = DSL.using(postgres, SQLDialect.POSTGRES, settings);
//execute some statements here
sql.execute(...);
//and don't forget to commit or the connection will not be returned to the pool
PostgresConnectionProvider p = (PostgresConnectionProvider) sql.configuration().connectionProvider();
p.commit();
And the ConnectionProvider:
public class PostgresConnectionProvider implements ConnectionProvider {
private static final Logger LOG = LoggerFactory.getLogger(PostgresConnectionProvider.class);
private final ThreadLocal<Connection> connections = new ThreadLocal<>();
private final BoneCP pool;
public PostgresConnectionProvider(String serverName, int port, String schema, String user, String password) throws SQLException {
this.pool = new ConnectionPool(getConnectionString(serverName, port, schema), user, password).pool;
}
private String getConnectionString(String serverName, int port, String schema) {
return "jdbc:postgresql://" + serverName + ":" + port + "/" + schema;
}
public void close() {
pool.shutdown();
}
public void commit() {
LOG.debug("Committing transaction in {}", Thread.currentThread());
try {
Connection connection = connections.get();
if (connection != null) {
connection.commit();
connection.close();
connections.set(null);
}
} catch (SQLException ex) {
throw new DataAccessException("Could not commit transaction in postgres pool", ex);
}
}
#Override
public Connection acquire() throws DataAccessException {
LOG.debug("Acquiring connection in {}", Thread.currentThread());
try {
Connection connection = connections.get();
if (connection == null) {
connection = pool.getConnection();
connection.setAutoCommit(false);
connections.set(connection);
}
return connection;
} catch (SQLException ex) {
throw new DataAccessException("Can't acquire connection from postgres pool", ex);
}
}
#Override
//no-op => the connection won't be released until it is commited
public void release(Connection connection) throws DataAccessException {
LOG.debug("Releasing connection in {}", Thread.currentThread());
}
}

Easiest way,(I have found) to use Spring Transactions with jOOQ, is given here: http://blog.liftoffllc.in/2014/06/jooq-and-transactions.html
Basically we implement a ConnectionProvider that uses org.springframework.jdbc.datasource.DataSourceUtils.doGetConnection(ds) method to find and return the DB connection that holds transaction created by Spring.
Create a TransactionManager bean for your DataSource, example shown below:
<bean
id="dataSource"
class="org.apache.tomcat.jdbc.pool.DataSource"
destroy-method="close"
p:driverClassName="com.mysql.jdbc.Driver"
p:url="mysql://locahost:3306/db_name"
p:username="root"
p:password="root"
p:initialSize="2"
p:maxActive="10"
p:maxIdle="5"
p:minIdle="2"
p:testOnBorrow="true"
p:validationQuery="/* ping */ SELECT 1"
/>
<!-- Configure the PlatformTransactionManager bean -->
<bean
id="transactionManager"
class="org.springframework.jdbc.datasource.DataSourceTransactionManager"
p:dataSource-ref="dataSource"
/>
<!-- Scan for the Transactional annotation -->
<tx:annotation-driven/>
Now you can annotate all the classes or methods which uses jOOQ's DSLContext with
#Transactional(rollbackFor = Exception.class)
And while creating the DSLContext object jOOQ will make use of the transaction created by Spring.

Though its an old question, Please look at this link to help configure JOOQ to use spring provided transaction manager. Your datasource and DSLContext have to be aware of Transacation.
https://www.baeldung.com/jooq-with-spring
You may have to change
#Bean
public DefaultDSLContext dsl() {
    return new DefaultDSLContext(configuration());
}
to
#Bean
public DSLContext dsl() {
    return new DefaultDSLContext(configuration());
}

Sleep Connection in MySql for long time leads to Slow process in Hibernate

I am using Hibernate in my application,
My connection code is as follows,
public class DBConnection{
private static SessionFactory factory;
private static ServiceRegistry serviceRegistry;
public DBConnection()
{
try
{
factory = new Configuration().configure().buildSessionFactory();
}
catch (Throwable ex) {
System.err.println("Failed to create sessionFactory object." + ex);
throw new ExceptionInInitializerError(ex);
}
}
public Session getSession()
{
return factory.openSession();
}
// Call this during shutdown
public static void close() {
factory.close();
serviceRegistry=null;
factory=null;
}
}
My Hibernate config file is ,
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-configuration SYSTEM
"http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
<session-factory>
<property name="hibernate.dialect">
org.hibernate.dialect.MySQLDialect
</property>
<property name="hibernate.connection.driver_class">
com.mysql.jdbc.Driver
</property>
<!-- Assume test is the database name -->
<property name="hibernate.connection.url">
jdbc:mysql://localhost:3307/Test
</property>
<property name="hibernate.connection.username">
root
</property>
<property name="hibernate.connection.password">
root
</property>
<property name=" hibernate.dbcp.max Wait">100</property>
</session-factory>
</hibernate-configuration>
The sample code for this process is
public String showurl(int id)
{
int i = 1;
String url= "";
Transaction tx= null;
Session session = null;
try
{
session = new DBConnection().getSession();
tx = session.beginTransaction();
Query query = session.createQuery(" FROM Test WHERE ID = :id");
query.setInteger("id", id);
List<Test> testlist= query.list();
for(Test nl:testlist)
{
url= nl.geturl();
}
tx.commit();
session.close();
DBConnection.close();
}catch(Exception ex)
{
if(tx!=null) tx.rollback();
session.close();
DBConnection.close();
ex.printStackTrace();
}
finally
{
if(tx!=null)
{
tx=null;
}
if(session.isOpen())
{
session.close();
}
if(session!=null)
{
session= null;
}
}
return url;
}
My problem here is , due to lot of sleep queries in the Database leads to slow down the process. How to solve this in my Application. I have more than 50 users using the application at the same time. how to solve this problem?
While Using this I am getting the following error frequently,
SEVERE: Servlet.service() for servlet [jsp] in context with path [] threw exception [org.hibernate.service.UnknownServiceException: Unknown service requested [org.hibernate.stat.spi.StatisticsImplementor]] with root cause
org.hibernate.service.UnknownServiceException: Unknown service requested [org.hibernate.stat.spi.StatisticsImplementor]
at org.hibernate.service.internal.AbstractServiceRegistryImpl.getService(AbstractServiceRegistryImpl.java:126)
at org.hibernate.internal.SessionFactoryImpl.getStatisticsImplementor(SessionFactoryImpl.java:1468)
at org.hibernate.internal.SessionFactoryImpl.getStatistics(SessionFactoryImpl.java:1464)
at org.hibernate.internal.SessionImpl.close(SessionImpl.java:346)
Any suggestion is highly appreciated.
Cheers!!

I would start from using other connection pool manager than Hibernate's build-in one - It it not design for production use. Try to use C3P0. Here is little hint how to configure it for hibernate. More informations can be found here
EDIT:
I have just noticed, that you are creating new session factory everytime you want to operate od db. That is SO WRONG! You should have only ONE instance of session factory, as service or application scope static field, and later use that for creating sessions as needed.
public static SessionFactory getSessionFactory(){
if (factory == null) {
try {
factory = new Configuration().configure().buildSessionFactory();
} catch (Throwable ex) {
System.err.println("Failed to create sessionFactory object." + ex);
throw new ExceptionInInitializerError(ex);
}
}
return factory;
}
public static Session getSession() {
return getSessionFactory().openSession();
}
from code use getSession() directly.

java.sql.SQLException: Io exception: Connection reset by peer: socket write error

I am using oracle 11g,hibernate 3 and jsf2.I deployed my application on was7.Every thing is going well but when i try to login after 5-6 hours it is gives me error
ERROR org.hibernate.util.JDBCExceptionReporter - Io exception: Connection reset by peer: socket write error
[5/28/13 11:31:25:048 IST] 00000024 SystemErr R org.hibernate.exception.GenericJDBCException: could not execute query
at org.hibernate.exception.SQLStateConverter.handledNonSpecificException(SQLStateConverter.java:126)
at org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:114)
at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:66)
at org.hibernate.loader.Loader.doList(Loader.java:2231)
at org.hibernate.loader.Loader.listIgnoreQueryCache(Loader.java:2125)
at org.hibernate.loader.Loader.list(Loader.java:2120)
at org.hibernate.loader.hql.QueryLoader.list(QueryLoader.java:401)
at org.hibernate.hql.ast.QueryTranslatorImpl.list(QueryTranslatorImpl.java:361)
at org.hibernate.engine.query.HQLQueryPlan.performList(HQLQueryPlan.java:196)
at org.hibernate.impl.SessionImpl.list(SessionImpl.java:1148)
at org.hibernate.impl.QueryImpl.list(QueryImpl.java:102)
I unable to find out how this error to solve.Please help me.Thanks in advance.
Now i have solved this problem by code but i don'nt know is it proper way or not.will you suggest me, i should continue with this solution on not.
public class ApplicationUtilityBean implements Serializable {
private SessionFactory sessionFactory;
private AnnotationConfiguration cfg;
public String filePath;
private String realPath = Config.PATH;
public ApplicationUtilityBean() throws URISyntaxException {
getConnection();
}
public void getConnection() {
URL r = this.getClass().getClassLoader().getResource("hibernate.cfg.xml");
cfg = new AnnotationConfiguration();
cfg.configure(r);
String pwd = cfg.getProperty("hibernate.connection.password");
TripleDESEncryption tripledesenc = null;
try {
tripledesenc = new TripleDESEncryption();
} catch (Exception e) {
e.printStackTrace();
}
cfg.setProperty("hibernate.connection.password",
tripledesenc.decrypt(pwd));
sessionFactory = cfg.buildSessionFactory();
System.out.println("cfg: " + cfg);
System.out.println("sessionFactory: " + sessionFactory);
}
public Session getSession() {
System.out.println("Going to get session");
Session session = null;
try {
System.out.println("cfg is: " + cfg);
System.out.println("sessionFactory: " + sessionFactory);
session = sessionFactory.openSession();
if(session != null){
try {
Transaction trxn = session.beginTransaction();
Query queryResult = session.createSQLQuery("select * from dual");
List<GTS_USER>listgtsuser = queryResult.list();
} catch (Exception e) {
e.printStackTrace();
System.out.println("Creating new connection............");
session.close();
sessionFactory.close();
getConnection();
session = sessionFactory.openSession();
}
}
} catch (Exception e) {
e.printStackTrace();
}
return session;
}
}
and my hibernate config file is
<hibernate-configuration>
<session-factory>
<property name="hibernate.cache.region.factory_class">net.sf.ehcache.hibernate.EhCacheRegionFactory</property>
<property name="hibernate.cache.use_query_cache">true</property>
<property name="hibernate.cache.use_second_level_cache">true</property>
<property name="hibernate.connection.driver_class">oracle.jdbc.OracleDriver</property>
<property name="hibernate.connection.url">jdbc:oracle:thin:#xxxxxxxxx:1521:HMS</property>
<property name="hibernate.connection.username">xxxxx</property>
<property name="hibernate.connection.password">xxxxxxxxxxx</property>
<property name="hibernate.connection.pool_size">10</property>
<property name="show_sql">true</property>
<property name="dialect">org.hibernate.dialect.OracleDialect</property>
<property name="hibernate.hbm2ddl.auto">update</property>

You are probably facing a database connection timeout. On every databases there is a timeout when a connection is open and there is no activity for a certain period. You need a connection pool manager.
If you install c3p0 and configure it correctly it will allow hibernate to keep your connection alive and/or re-open it when you need it.
Here is an example for MySQL and Hibernate indeed but it is the same. You have to include c3p0.jar and also add this to your hibernade configuration file :
<property name="c3p0.min_size">5</property>
<property name="c3p0.max_size">20</property>
<property name="c3p0.timeout">1800</property>
<property name="c3p0.max_statements">50</property>
<property name="hibernate.connection.provider_class">org.hibernate.connection.C3P0ConnectionProvider</property>
Make sure to configure c3p0.timeout according to your database!

The issue here is that an idle connection will be closed by the database server. The application doesn't come to know about it and tries to use a stale connection (from the pool that was created during initialization). The fix for this is to configure the connection pool to do a test for liveness (usually by firing a simple select query) before using a connection from the pool.
How to do this varies on how you have setup the datasource / connection pooling. If you provide more details on it I can provide more specific instructions.

According to #BalusC
If your application is supposed to run a relatively long time and to connect the DB fairly often, then consider using a connection pool to improve connecting performance. If your application is a webapplication, then take a look in the appserver's documentation, it usually provides a connection pooling facility in flavor of a DataSource. If it is a client application, then look for 3rd party connection pooling libraries which have proven their robustness with years, such as Apache Commons DBCP (commonly used, used in lot appservers), C3P0 (known from Hibernate) and Proxool (if you want XA connections).