Difficulties Session Hibernate

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My web application uses Hibernate 4.3 and makes Connection Pool control using C3P0.

The difficulties happen recurrently and unfortunately I can not find what the problem that causes such errors.

Follow one of the mistakes:

org.hibernate.SessionException: Session is closed!
    at org.hibernate.internal.AbstractSessionImpl.errorIfClosed(AbstractSessionImpl.java:133)
    at org.hibernate.internal.SessionImpl.getTransactionCoordinator(SessionImpl.java:2065)
    at org.hibernate.loader.Loader.getResultSet(Loader.java:2065)
    at org.hibernate.loader.Loader.executeQueryStatement(Loader.java:1862)
    at org.hibernate.loader.Loader.executeQueryStatement(Loader.java:1838)
    at org.hibernate.loader.Loader.doQuery(Loader.java:909)
    at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:354)
    at org.hibernate.loader.Loader.doList(Loader.java:2551)
    at org.hibernate.loader.Loader.doList(Loader.java:2537)
    at org.hibernate.loader.Loader.listIgnoreQueryCache(Loader.java:2367)
    at org.hibernate.loader.Loader.list(Loader.java:2362)
    at org.hibernate.loader.hql.QueryLoader.list(QueryLoader.java:496)
    at org.hibernate.hql.internal.ast.QueryTranslatorImpl.list(QueryTranslatorImpl.java:387)
    at org.hibernate.engine.query.spi.HQLQueryPlan.performList(HQLQueryPlan.java:229)
    at org.hibernate.internal.SessionImpl.list(SessionImpl.java:1260)
    at org.hibernate.internal.QueryImpl.list(QueryImpl.java:103)
    at br.com.portalserver.dao.PedidoItemDAO.selectItensPedido(PedidoItemDAO.java:37)
    at br.com.forcavendasweb.controller.PedidosFVController.carregaDadosCliente(PedidosFVController.java:498)
    at br.com.forcavendasweb.controller.PedidosFVController.doGet(PedidosFVController.java:193)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:687)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:790)
    at org.apache.catalina.core.StandardWrapper.service(StandardWrapper.java:1682)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:318)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:160)
    at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:734)
    at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:673)
    at com.sun.enterprise.web.WebPipeline.invoke(WebPipeline.java:99)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:174)
    at org.apache.catalina.connector.CoyoteAdapter.doService(CoyoteAdapter.java:416)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:283)
    at com.sun.enterprise.v3.services.impl.ContainerMapper$HttpHandlerCallable.call(ContainerMapper.java:459)
    at com.sun.enterprise.v3.services.impl.ContainerMapper.service(ContainerMapper.java:167)
    at org.glassfish.grizzly.http.server.HttpHandler.runService(HttpHandler.java:206)
    at org.glassfish.grizzly.http.server.HttpHandler.doHandle(HttpHandler.java:180)
    at org.glassfish.grizzly.http.server.HttpServerFilter.handleRead(HttpServerFilter.java:235)
    at org.glassfish.grizzly.filterchain.ExecutorResolver$9.execute(ExecutorResolver.java:119)
    at org.glassfish.grizzly.filterchain.DefaultFilterChain.executeFilter(DefaultFilterChain.java:283)
    at org.glassfish.grizzly.filterchain.DefaultFilterChain.executeChainPart(DefaultFilterChain.java:200)
    at org.glassfish.grizzly.filterchain.DefaultFilterChain.execute(DefaultFilterChain.java:132)
    at org.glassfish.grizzly.filterchain.DefaultFilterChain.process(DefaultFilterChain.java:111)
    at org.glassfish.grizzly.ProcessorExecutor.execute(ProcessorExecutor.java:77)
    at org.glassfish.grizzly.nio.transport.TCPNIOTransport.fireIOEvent(TCPNIOTransport.java:536)
    at org.glassfish.grizzly.strategies.AbstractIOStrategy.fireIOEvent(AbstractIOStrategy.java:112)
    at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy.run0(WorkerThreadIOStrategy.java:117)
    at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy.access$100(WorkerThreadIOStrategy.java:56)
    at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy$WorkerThreadRunnable.run(WorkerThreadIOStrategy.java:137)
    at org.glassfish.grizzly.threadpool.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:591)
    at org.glassfish.grizzly.threadpool.AbstractThreadPool$Worker.run(AbstractThreadPool.java:571)
    at java.lang.Thread.run(Thread.java:748)

Follows parts of the codes:

Hibernateutil.xml

 public class HibernateUtil {

     private static SessionFactory sessionFactory;
     private static ServiceRegistry serviceRegistry;
     private static Session session;

     public static Session getSession() {
         if (session == null || !session.isOpen()) {
             session = HibernateUtil.getFactory().openSession();
         }
         return session;
     }

     public static void closeSession() {
         if (session.isOpen()) {
             session.close();
         }
     }

     public static void commitSession() {
         if (session.getTransaction().wasCommitted()) {
             session.getTransaction().commit();
         }
     }

     public static SessionFactory getFactory() {
         if (sessionFactory == null || sessionFactory.isClosed()) {
             sessionFactory = HibernateUtil.buildSessionFactory();
         }

         return sessionFactory;
     }

     public static void closeFactory() {
         sessionFactory.close();
         StandardServiceRegistryBuilder.destroy(serviceRegistry);
     }

     private static SessionFactory buildSessionFactory() {
         try {
             Configuration configuration = new Configuration().configure();
             serviceRegistry = new StandardServiceRegistryBuilder().applySettings(configuration.getProperties()).build();

             SessionFactory factory = configuration.buildSessionFactory(serviceRegistry);
             return factory;

         } catch (HibernateException ex) {
             System.err.println("FALHA NA CRIACAO DA SESSION FACTORY = " + ex);

             throw new ExceptionInInitializerError(ex);
         }
     } }

C3P0 Connection Pool Settings inside Hibernate.cfg.xml

<property name="hibernate.connection.provider_class">org.hibernate.connection.C3P0ConnectionProvider</property>
<property name="hibernate.c3p0.acquireIncrement">2</property>
<property name="hibernate.c3p0.initialPoolSize">3</property>
<property name="hibernate.c3p0.minPoolSize">3</property>
<property name="hibernate.c3p0.maxPoolSize">8</property>
<property name="hibernate.c3p0.maxIdleTime">1200</property>
<property name="hibernate.c3p0.maxConnectionAge">1200</property>
<property name="hibernate.c3p0.acquireRetryAttempts">1</property>
<property name="hibernate.c3p0.acquireRetryDelay">250</property>

DAO Methods:

public List<PedidoItem> selectItensPedido(Pedido ped) {
        List<PedidoItem> listaItens = Singleton.getListarItens();
        String hql = "FROM PedidoItem WHERE numped = :numped ORDER BY idpit ASC";

        session = HibernateUtil.getSession();

        try {
            listaItens = session
                    .createQuery(hql)
                    .setParameter("numped", ped.getIdped())
                    .list();

        } catch (RuntimeException erro) {
            throw erro;
        }

        return listaItens;
    }


public void editar(Entidade entidade) {
        session = HibernateUtil.getSession();
        try {
            transaction = session.beginTransaction();

            session.update(entidade);

            if (!transaction.wasCommitted()) {
                transaction.commit();
            }

        } catch (RuntimeException erro) {
            if (transaction != null) {
                try {
                    transaction.rollback();

                } catch (Exception ex) {
                    System.err.println("==> ERRO AO FAZER ROLLBACK: " + ex.toString());
                }
            }
            System.err.println("==> ERRO ORIGINAL AO EXECUTAR A QUERY: " + erro.toString());
            throw erro;

        } finally {
            HibernateUtil.closeSession();

        }
    }

After this, the error that happens is as follows:

org.hibernate.exception.JDBCConnectionException: Could not open connection
    at org.hibernate.exception.internal.SQLStateConversionDelegate.convert(SQLStateConversionDelegate.java:132)
    at org.hibernate.exception.internal.StandardSQLExceptionConverter.convert(StandardSQLExceptionConverter.java:49)
    at org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:126)
    at org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:112)
    at org.hibernate.engine.jdbc.internal.LogicalConnectionImpl.obtainConnection(LogicalConnectionImpl.java:235)
    at org.hibernate.engine.jdbc.internal.LogicalConnectionImpl.getConnection(LogicalConnectionImpl.java:171)
    at org.hibernate.engine.transaction.internal.jdbc.JdbcTransaction.doBegin(JdbcTransaction.java:67)
    at org.hibernate.engine.transaction.spi.AbstractTransactionImpl.begin(AbstractTransactionImpl.java:162)
    at org.hibernate.internal.SessionImpl.beginTransaction(SessionImpl.java:1431)
    at br.com.portalserver.dao.PedidoItemDAO.alterarItem(PedidoItemDAO.java:164)
    at br.com.forcavendasweb.controller.PedidosFVController.doPost(PedidosFVController.java:335)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:707)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:790)
    at org.apache.catalina.core.StandardWrapper.service(StandardWrapper.java:1682)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:318)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:160)
    at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:734)
    at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:673)
    at com.sun.enterprise.web.WebPipeline.invoke(WebPipeline.java:99)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:174)
    at org.apache.catalina.connector.CoyoteAdapter.doService(CoyoteAdapter.java:416)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:283)
    at com.sun.enterprise.v3.services.impl.ContainerMapper$HttpHandlerCallable.call(ContainerMapper.java:459)
    at com.sun.enterprise.v3.services.impl.ContainerMapper.service(ContainerMapper.java:167)
    at org.glassfish.grizzly.http.server.HttpHandler.runService(HttpHandler.java:206)
    at org.glassfish.grizzly.http.server.HttpHandler.doHandle(HttpHandler.java:180)
    at org.glassfish.grizzly.http.server.HttpServerFilter.handleRead(HttpServerFilter.java:235)
    at org.glassfish.grizzly.filterchain.ExecutorResolver$9.execute(ExecutorResolver.java:119)
    at org.glassfish.grizzly.filterchain.DefaultFilterChain.executeFilter(DefaultFilterChain.java:283)
    at org.glassfish.grizzly.filterchain.DefaultFilterChain.executeChainPart(DefaultFilterChain.java:200)
    at org.glassfish.grizzly.filterchain.DefaultFilterChain.execute(DefaultFilterChain.java:132)
    at org.glassfish.grizzly.filterchain.DefaultFilterChain.process(DefaultFilterChain.java:111)
    at org.glassfish.grizzly.ProcessorExecutor.execute(ProcessorExecutor.java:77)
    at org.glassfish.grizzly.nio.transport.TCPNIOTransport.fireIOEvent(TCPNIOTransport.java:536)
    at org.glassfish.grizzly.strategies.AbstractIOStrategy.fireIOEvent(AbstractIOStrategy.java:112)
    at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy.run0(WorkerThreadIOStrategy.java:117)
    at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy.access$100(WorkerThreadIOStrategy.java:56)
    at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy$WorkerThreadRunnable.run(WorkerThreadIOStrategy.java:137)
    at org.glassfish.grizzly.threadpool.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:591)
    at org.glassfish.grizzly.threadpool.AbstractThreadPool$Worker.run(AbstractThreadPool.java:571)
    at java.lang.Thread.run(Thread.java:748)
Caused by: com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure
The last packet successfully received from the server was 358,660 milliseconds ago.  The last packet sent successfully to the server was 23,959 milliseconds ago.
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
    at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
    at com.mysql.jdbc.Util.handleNewInstance(Util.java:425)
    at com.mysql.jdbc.SQLError.createCommunicationsException(SQLError.java:989)
    at com.mysql.jdbc.MysqlIO.reuseAndReadPacket(MysqlIO.java:3559)
    at com.mysql.jdbc.MysqlIO.reuseAndReadPacket(MysqlIO.java:3459)
    at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3900)
    at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:2527)
    at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2680)
    at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2483)
    at com.mysql.jdbc.ConnectionImpl.setAutoCommit(ConnectionImpl.java:4819)
    at com.mchange.v2.c3p0.impl.NewProxyConnection.setAutoCommit(NewProxyConnection.java:912)
    at org.hibernate.c3p0.internal.C3P0ConnectionProvider.getConnection(C3P0ConnectionProvider.java:94)
    at org.hibernate.internal.AbstractSessionImpl$NonContextualJdbcConnectionAccess.obtainConnection(AbstractSessionImpl.java:380)
    at org.hibernate.engine.jdbc.internal.LogicalConnectionImpl.obtainConnection(LogicalConnectionImpl.java:228)
    ... 36 more
Caused by: java.net.SocketException: Operation timed out (Read failed)
    at java.net.SocketInputStream.socketRead0(Native Method)
    at java.net.SocketInputStream.socketRead(SocketInputStream.java:116)
    at java.net.SocketInputStream.read(SocketInputStream.java:171)
    at java.net.SocketInputStream.read(SocketInputStream.java:141)
    at com.mysql.jdbc.util.ReadAheadInputStream.fill(ReadAheadInputStream.java:101)
    at com.mysql.jdbc.util.ReadAheadInputStream.readFromUnderlyingStreamIfNecessary(ReadAheadInputStream.java:144)
    at com.mysql.jdbc.util.ReadAheadInputStream.read(ReadAheadInputStream.java:174)
    at com.mysql.jdbc.MysqlIO.readFully(MysqlIO.java:3008)
    at com.mysql.jdbc.MysqlIO.reuseAndReadPacket(MysqlIO.java:3469)
    ... 46 more

WARN:   SQL Error: 1205, SQLState: 40001
ERROR:   Lock wait timeout exceeded; try restarting transaction
Grave:   ==> ERRO ORIGINAL AO EXECUTAR A QUERY: org.hibernate.exception.LockAcquisitionException: could not execute statement
Advertência:   StandardWrapperValve[br.com.forcavendasweb.controller.PedidosFVController]: Servlet.service() for servlet br.com.forcavendasweb.controller.PedidosFVController threw exception
org.hibernate.exception.LockAcquisitionException: could not execute statement
    at org.hibernate.dialect.MySQLDialect$1.convert(MySQLDialect.java:451)
    at org.hibernate.exception.internal.StandardSQLExceptionConverter.convert(StandardSQLExceptionConverter.java:49)
    at org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:126)
    at org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:112)
    at org.hibernate.engine.jdbc.internal.ResultSetReturnImpl.executeUpdate(ResultSetReturnImpl.java:190)
    at org.hibernate.hql.internal.ast.exec.BasicExecutor.doExecute(BasicExecutor.java:109)
    at org.hibernate.hql.internal.ast.exec.BasicExecutor.execute(BasicExecutor.java:78)
    at org.hibernate.hql.internal.ast.exec.DeleteExecutor.execute(DeleteExecutor.java:125)
    at org.hibernate.hql.internal.ast.QueryTranslatorImpl.executeUpdate(QueryTranslatorImpl.java:445)
    at org.hibernate.engine.query.spi.HQLQueryPlan.performExecuteUpdate(HQLQueryPlan.java:347)
    at org.hibernate.internal.SessionImpl.executeUpdate(SessionImpl.java:1282)
    at org.hibernate.internal.QueryImpl.executeUpdate(QueryImpl.java:118)
    at br.com.portalserver.dao.PedidoItemDAO.excluirItem(PedidoItemDAO.java:138)
    at br.com.forcavendasweb.controller.PedidosFVController.doGet(PedidosFVController.java:201)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:687)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:790)
    at org.apache.catalina.core.StandardWrapper.service(StandardWrapper.java:1682)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:318)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:160)
    at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:734)
    at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:673)
    at com.sun.enterprise.web.WebPipeline.invoke(WebPipeline.java:99)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:174)
    at org.apache.catalina.connector.CoyoteAdapter.doService(CoyoteAdapter.java:416)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:283)
    at com.sun.enterprise.v3.services.impl.ContainerMapper$HttpHandlerCallable.call(ContainerMapper.java:459)
    at com.sun.enterprise.v3.services.impl.ContainerMapper.service(ContainerMapper.java:167)
    at org.glassfish.grizzly.http.server.HttpHandler.runService(HttpHandler.java:206)
    at org.glassfish.grizzly.http.server.HttpHandler.doHandle(HttpHandler.java:180)
    at org.glassfish.grizzly.http.server.HttpServerFilter.handleRead(HttpServerFilter.java:235)
    at org.glassfish.grizzly.filterchain.ExecutorResolver$9.execute(ExecutorResolver.java:119)
    at org.glassfish.grizzly.filterchain.DefaultFilterChain.executeFilter(DefaultFilterChain.java:283)
    at org.glassfish.grizzly.filterchain.DefaultFilterChain.executeChainPart(DefaultFilterChain.java:200)
    at org.glassfish.grizzly.filterchain.DefaultFilterChain.execute(DefaultFilterChain.java:132)
    at org.glassfish.grizzly.filterchain.DefaultFilterChain.process(DefaultFilterChain.java:111)
    at org.glassfish.grizzly.ProcessorExecutor.execute(ProcessorExecutor.java:77)
    at org.glassfish.grizzly.nio.transport.TCPNIOTransport.fireIOEvent(TCPNIOTransport.java:536)
    at org.glassfish.grizzly.strategies.AbstractIOStrategy.fireIOEvent(AbstractIOStrategy.java:112)
    at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy.run0(WorkerThreadIOStrategy.java:117)
    at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy.access$100(WorkerThreadIOStrategy.java:56)
    at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy$WorkerThreadRunnable.run(WorkerThreadIOStrategy.java:137)
    at org.glassfish.grizzly.threadpool.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:591)
    at org.glassfish.grizzly.threadpool.AbstractThreadPool$Worker.run(AbstractThreadPool.java:571)
    at java.lang.Thread.run(Thread.java:748)
Caused by: com.mysql.jdbc.exceptions.jdbc4.MySQLTransactionRollbackException: Lock wait timeout exceeded; try restarting transaction
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
    at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
    at com.mysql.jdbc.Util.handleNewInstance(Util.java:425)
    at com.mysql.jdbc.Util.getInstance(Util.java:408)
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:951)
    at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3973)
    at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3909)
    at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:2527)
    at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2680)
    at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2487)
    at com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:1858)
    at com.mysql.jdbc.PreparedStatement.executeUpdateInternal(PreparedStatement.java:2079)
    at com.mysql.jdbc.PreparedStatement.executeUpdateInternal(PreparedStatement.java:2013)
    at com.mysql.jdbc.PreparedStatement.executeLargeUpdate(PreparedStatement.java:5104)
    at com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:1998)
    at com.mchange.v2.c3p0.impl.NewProxyPreparedStatement.executeUpdate(NewProxyPreparedStatement.java:147)
    at org.hibernate.engine.jdbc.internal.ResultSetReturnImpl.executeUpdate(ResultSetReturnImpl.java:187)
    ... 39 more

I’ve been racking my brain for days, testing and testing tirelessly, and such a mistake continues to torture me. I don’t know what else could cause such trouble.

Please, if anyone can shed some light.

Thank you very much

java hibernate session c3p0

  • Your error seems to be related to database connection. You have tested the same?

  • This must be competition in the static session variable. If you are receiving this error in the middle of multiple requests, it may occur that your session will close while you are trying to make a query (for example, when an error occurs in another request). The main culprit of this in your code is the use of static variables for Session, because the same Session should not be used by different threads.

  • @Dherik I will make the suggested change. I confess that I had not thought about this issue. I will report what will be the result. Thank you very much

  • @Rogérioeduardschaefer, working let me know, that I prepare a better answer or try something else if it doesn’t work.

  • @Douglas, the connection is ok. I did not find any error regarding the connection to the Bank. Anyway, I will make more tests and I will pay attention to this issue. Thank you very much

  • @Dherik, I turned the Session into non-static and the above errors no longer occurred. But my application contains several requests (select, Insert, update, delet) and with this the number of sessions opened in the database increased more than 200 times. Sessions being nonstatic do not reuse open sessions in BD and each request, open new sessions.

  • Right. It’s probably now a problem of not closing sessions. You need to close the session at each order of transaction. You need to create this control to open a new session to each thread, start the transaction, do the operation you want to do, commit the transaction (or rollback in case of error) and close the session at the end of everything.

  • Let’s go continue this discussion in chat.

Show 3 more comments

1 answer

1

Hello,

I believe that the problem you are having there is competition with the variable session. You are sharing the same session between various classes and methods, and at some point one of them is closing the session and impacting the other methods that are trying to use it.

This is because of this code:

private static Session session;

Try removing this field session from within the HibernateUtil and use the same instance of Session only in the method that uses it. Something like this:

public List<PedidoItem> selectItensPedido(Pedido ped) {
        List<PedidoItem> listaItens = Singleton.getListarItens();
        String hql = "FROM PedidoItem WHERE numped = :numped ORDER BY idpit ASC";

        Session session = HibernateUtil.getFactory().openSession();

And at the end of the method, you close the session within the finally.

And in Hibernateutil it would be:

public static Session openSession() {
     return HibernateUtil.getFactory().openSession();;
}

If you’re having trouble managing the session and transaction, I recommend using a framework like Spring to take care of this bureaucracy for you.

  • I made the changes suggested by you and the problems mentioned above no longer occurred. I believe I have solved this issue. I’ll keep testing. Thank you so much for the excellent help.

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