Я получил исключение при добавлении C3P0 в спящий режим

Question

У меня есть приложение, которое использует Hibernate (открытие и закрытие сеансов), но некоторые люди рекомендуют мне использовать C3P0.Я искал в интернете, и я обнаружил, что только с этими строками все приложение должно работать как прежде, чем менять его, но с «Conecction pool».

<property name="connection.provider_class">
       org.hibernate.connection.C3P0ConnectionProvider
    </property>
    <property name="hibernate.c3p0.acquire_increment">1</property>
        <property name="hibernate.c3p0.idle_test_period">60</property> <!-- seconds -->
        <property name="hibernate.c3p0.min_size">5</property>
        <property name="hibernate.c3p0.max_size">10</property>
        <property name="hibernate.c3p0.max_statements">50</property>
        <property name="hibernate.c3p0.timeout">0</property> <!-- seconds -->
        <property name="hibernate.c3p0.acquireRetryAttempts">1</property>
        <property name="hibernate.c3p0.acquireRetryDelay">250</property>

Но моя проблема в том, что когда я добавляюэто в hibernate.cfg.xml.Я не знаю почему, но когда приложение достигает этой строки:

SessionFactory sessionFactory = SessionFactoryUtil.getSessionFactory();

Выдает это исключение:

 Initial SessionFactory creation failed.org.hibernate.service.spi.ServiceException: Unable to create requested service [org.hibernate.service.jdbc.connections.spi.ConnectionProvider]
sep 22, 2018 4:34:48 PM org.apache.catalina.core.StandardWrapperValve invoke
GRAVE: El Servlet.service() para el servlet [Servlets.Login] en el contexto con ruta [/Just4Goals] lanzó la excepción [La ejecución del Servlet lanzó una excepción] con causa raíz
java.lang.ClassNotFoundException: Could not load requested class : org.hibernate.service.jdbc.connections.internal.C3P0ConnectionProvider
    at org.hibernate.service.classloading.internal.ClassLoaderServiceImpl$1.findClass(ClassLoaderServiceImpl.java:99)
    at java.lang.ClassLoader.loadClass(Unknown Source)
    at java.lang.ClassLoader.loadClass(Unknown Source)
    at org.hibernate.service.classloading.internal.ClassLoaderServiceImpl.classForName(ClassLoaderServiceImpl.java:138)
    at org.hibernate.service.jdbc.connections.internal.ConnectionProviderInitiator.instantiateExplicitConnectionProvider(ConnectionProviderInitiator.java:189)
    at org.hibernate.service.jdbc.connections.internal.ConnectionProviderInitiator.initiateService(ConnectionProviderInitiator.java:114)
    at org.hibernate.service.jdbc.connections.internal.ConnectionProviderInitiator.initiateService(ConnectionProviderInitiator.java:54)
    at org.hibernate.service.internal.StandardServiceRegistryImpl.initiateService(StandardServiceRegistryImpl.java:69)
    at org.hibernate.service.internal.AbstractServiceRegistryImpl.createService(AbstractServiceRegistryImpl.java:177)
    at org.hibernate.service.internal.AbstractServiceRegistryImpl.initializeService(AbstractServiceRegistryImpl.java:150)
    at org.hibernate.service.internal.AbstractServiceRegistryImpl.getService(AbstractServiceRegistryImpl.java:131)
    at org.hibernate.engine.jdbc.internal.JdbcServicesImpl.buildJdbcConnectionAccess(JdbcServicesImpl.java:223)
    at org.hibernate.engine.jdbc.internal.JdbcServicesImpl.configure(JdbcServicesImpl.java:89)
    at org.hibernate.service.internal.StandardServiceRegistryImpl.configureService(StandardServiceRegistryImpl.java:75)
    at org.hibernate.service.internal.AbstractServiceRegistryImpl.initializeService(AbstractServiceRegistryImpl.java:159)
    at org.hibernate.service.internal.AbstractServiceRegistryImpl.getService(AbstractServiceRegistryImpl.java:131)
    at org.hibernate.cfg.SettingsFactory.buildSettings(SettingsFactory.java:71)
    at org.hibernate.cfg.Configuration.buildSettingsInternal(Configuration.java:2273)
    at org.hibernate.cfg.Configuration.buildSettings(Configuration.java:2269)
    at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1738)
    at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1778)
    at tratadoDatosBD.SessionFactoryUtil.<clinit>(SessionFactoryUtil.java:72)
    at usersLogin.EncryptData.comprobarLogin(EncryptData.java:146)
    at Servlets.Login.Checklogin(Login.java:83)
    at Servlets.Login.doPost(Login.java:39)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:660)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:741)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:199)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:494)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:137)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92)
    at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:651)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343)
    at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:407)
    at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66)
    at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:754)
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1376)
    at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    at java.lang.Thread.run(Unknown Source)

Но приложение работает без проблем, когда я не добавляю свойства C3P0 в спящий режим.cfg.xml.

Может, я еще что-нибудь добавлю?Должен ли я изменить свой код, чтобы пул соединений работал?Почему это не работает?

Спасибо!