java.lang.NoClassDefFoundError

[Beacons]

Qualcuno ha mai riscontrato questa eccezione utilizzando Hibernate?

java.lang.NoClassDefFoundError: Could not initialize class dao.utenti.UtentiDAO
    action.utenti.Login.execute(Login.java:33)
    org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:425)
    org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:228)
    org.apache.struts.action.ActionServlet.process(ActionServlet.java:1913)
    org.apache.struts.action.ActionServlet.doGet(ActionServlet.java:449)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:617)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
    org.netbeans.modules.web.monitor.server.MonitorFilter.doFilter(MonitorFilter.java:390)