Hibernate – java.lang.ClassNotFoundException: org.hibernate.HibernateException

I am running a web application with hibernate and got stuck at this exception. Any help please?

java.lang.ClassNotFoundException: org.hibernate.HibernateException
at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1714)
at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1559)
at com.forum.dao.TopicDAO.findAll(TopicDAO.java:43)
at com.forum.servlets.Accueil.doGet(Accueil.java:23)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:621)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:222)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:123)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:99)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:953)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:408)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1008)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:589)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:312)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)

Here is TopicDAO.findALL()

public static List<Topic> findAll() {

    Session  s = HibernateUtils.getSession(); //TopicDAO.java:43
    Transaction tx = s.beginTransaction();
    List<Topic> objects = null;

    Query q = s.createQuery("from Topic");
    objects = q.list();
    tx.commit();

    return objects;
}

And, here is my servlet.doGet()

public void doGet( HttpServletRequest request, HttpServletResponse response ) throws ServletException, IOException {
    HttpSession session = request.getSession();

    TopicDAO td = new TopicDAO();
    List<Topic> listTopics = td.findAll();

    session.setAttribute( ATT_LIST_TOPICS, listTopics );

    this.getServletContext().getRequestDispatcher( ACCUEIL ).forward( request, response );
}

Here is my added Hibernate libraries: