[Hibernate] NoClassDefFoundError

[Ritchie Warsi]

I'm building my first Struts/Tiles/Hibernate application and ran into some problems.

I have a Businessclass that has a method for a List, I call on that method straight in my jsp. This same approach did work on another tutorial I was working on, but in my project now it isn't.

Here is the method in CustomerDAO.java:

public List getCustomerList()
{
/*
 * Use the ConnectionFactory to retrieve an open
 * Hibernate Session.
 * 
 */
Session session = null;
 
try
{
session = HibernateUtil.getSession();
/*
* Build HQL (Hibernate Query Language) query to retrieve a list
* of all the items currently stored by Hibernate.
 */
Query query = session.createQuery("select Customer from com.frontier.hibernate.Customer Customer order by Customer.customerid");
return query.list();
 
}
catch (HibernateException e)
{
System.err.println("Session not getted!" + e.getMessage());
throw new RuntimeException(e);
}
/*
 * Regardless of whether the above processing resulted in an Exception
 * or proceeded normally, we want to close the Hibernate session.  When
 * closing the session, we must allow for the possibility of a Hibernate
 * Exception.
 * 
 */
finally
{
if (session != null)
{
try
{
session.close();
}
catch (HibernateException e)
{
System.err.println("Hibernate Exception" + e.getMessage());
throw new RuntimeException(e);
}
 
}
}
}

This is my accOptions.jsp:

<%@ page import="com.frontier.hibernate.CustomerDAO" %>
<%@ page import="java.util.List" %>
<%
      /*
       * This code will generate a list of objects from the
       * database and place a reference to this list in the
       * request object.
       *
       */
      List customerList = CustomerDAO.getInstance().getCustomerList();
      
      request.setAttribute("customers", customerList);
      
   %>
<logic:iterate id="element" name="customers" scope="request" type="com.frontier.hibernate.Customer" indexId="toggle">
   <table>
   <tr><td>Name:</td><td><bean:write name="element" property="name" scope="request" /></td></tr>
   <tr><td>Address:</td><td><bean:write name="element" property="address" scope="request" /></td></tr>
   <tr><td>City:</td><td><bean:write name="element" property="city" scope="request" /></td></tr>
   <tr><td>Number of Mortgages:</td><td><bean:write name="element" property="noofmortgages" scope="request"  /></td></tr>
    </table>
</logic:iterate>

And this is my rather long (sorry for that) HibernateUtil.java:

/**
 * Basic Hibernate helper class, handles SessionFactory, Session and Transaction.
 * <p>
 * Uses a static initializer for the initial SessionFactory creation
 * and holds Session and Transactions in thread local variables. All
 * exceptions are wrapped in an unchecked InfrastructureException.
 *
 * @author [e-mail]
 */
public class HibernateUtil {
 
private static Log log = LogFactory.getLog(SessionFactory.class);
 
private static Configuration configuration;
private static SessionFactory sessionFactory;
private static final ThreadLocal threadSession = new ThreadLocal();
private static final ThreadLocal threadTransaction = new ThreadLocal();
private static final ThreadLocal threadInterceptor = new ThreadLocal();
 
// Create the initial SessionFactory from the default configuration files
static {
try {
//configuration = new Configuration();
sessionFactory = new Configuration().configure().buildSessionFactory();
// We could also let Hibernate bind it to JNDI:
// configuration.configure().buildSessionFactory()
} catch (Throwable ex) {
// We have to catch Throwable, otherwise we will miss
// NoClassDefFoundError and other subclasses of Error
log.error("Building SessionFactory failed.", ex);
throw new ExceptionInInitializerError(ex);
}
}


/**
 * Returns the SessionFactory used for this static class.
 *
 * @return SessionFactory
 */
public static SessionFactory getSessionFactory() {
   
/* Instead of a static variable, use JNDI:
SessionFactory sessions = null;
try {
Context ctx = new InitialContext();
String jndiName = "java:hibernate/HibernateFactory";
sessions = (SessionFactory)ctx.lookup(jndiName);
} catch (NamingException ex) {
throw new InfrastructureException(ex);
}
return sessions;
*/
return sessionFactory;
}
 
/**
 * Returns the original Hibernate configuration.
 *
 * @return Configuration
 */
public static Configuration getConfiguration() {
return configuration;
}
 
/**
 * Rebuild the SessionFactory with the static Configuration.
 *
 */
 public static void rebuildSessionFactory()
throws InfrastructureException {
synchronized(sessionFactory) {
try {
sessionFactory = getConfiguration().buildSessionFactory();
} catch (Exception ex) {
throw new InfrastructureException(ex);
}
}
 }
 
/**
 * Rebuild the SessionFactory with the given Hibernate Configuration.
 *
 * @param cfg
 */
 public static void rebuildSessionFactory(Configuration cfg)
throws InfrastructureException {
synchronized(sessionFactory) {
try {
sessionFactory = cfg.buildSessionFactory();
configuration = cfg;
} catch (Exception ex) {
throw new InfrastructureException(ex);
}
}
 }
 
/**
 * Retrieves the current Session local to the thread.
 * <p/>
 * If no Session is open, opens a new Session for the running thread.
 *
 * @return Session
 */
public static Session getSession()
throws InfrastructureException {
Session s = (Session) threadSession.get();
try {
if (s == null || s.isOpen() == false) {
log.debug("Opening new Session for this thread.");
if (getInterceptor() != null) {
log.debug("Using interceptor: " + getInterceptor().getClass());
s = getSessionFactory().openSession(getInterceptor());
} else {
s = getSessionFactory().openSession();
}
threadSession.set(s);
}
} catch (HibernateException ex) {
throw new InfrastructureException(ex);
}
return s;
}
 
/**
 * Closes the Session local to the thread.
 */
public static void closeSession()
throws InfrastructureException {
try {
Session s = (Session) threadSession.get();
threadSession.set(null);
if (s != null && s.isOpen()) {
log.debug("Closing Session of this thread.");
s.close();
}
} catch (HibernateException ex) {
throw new InfrastructureException(ex);
}
}
 
/**
 * Start a new database transaction.
 */
public static void beginTransaction()
throws InfrastructureException {
Transaction tx = (Transaction) threadTransaction.get();
try {
if (tx == null) {
log.debug("Starting new database transaction in this thread.");
tx = getSession().beginTransaction();
threadTransaction.set(tx);
}
} catch (HibernateException ex) {
throw new InfrastructureException(ex);
}
}
 
/**
 * Commit the database transaction.
 */
public static void commitTransaction()
throws InfrastructureException {
Transaction tx = (Transaction) threadTransaction.get();
try {
if ( tx != null && !tx.wasCommitted()
&& !tx.wasRolledBack() ) {
log.debug("Committing database transaction of this thread.");
tx.commit();
}
threadTransaction.set(null);
} catch (HibernateException ex) {
rollbackTransaction();
throw new InfrastructureException(ex);
}
}
 
/**
 * Commit the database transaction.
 */
public static void rollbackTransaction()
throws InfrastructureException {
Transaction tx = (Transaction) threadTransaction.get();
try {
threadTransaction.set(null);
if ( tx != null && !tx.wasCommitted() && !tx.wasRolledBack() ) {
log.debug("Tyring to rollback database transaction of this thread.");
tx.rollback();
}
} catch (HibernateException ex) {
throw new InfrastructureException(ex);
} finally {
closeSession();
}
}
 
/**
 * Reconnects a Hibernate Session to the current Thread.
 *
 * @param session The Hibernate Session to be reconnected.
 */
public static void reconnect(Session session)
throws InfrastructureException {
try {
session.reconnect();
threadSession.set(session);
} catch (HibernateException ex) {
throw new InfrastructureException(ex);
}
}
 
/**
 * Disconnect and return Session from current Thread.
 *
 * @return Session the disconnected Session
 */
public static Session disconnectSession()
throws InfrastructureException {
 
Session session = getSession();
try {
threadSession.set(null);
if (session.isConnected() && session.isOpen())
session.disconnect();
} catch (HibernateException ex) {
throw new InfrastructureException(ex);
}
return session;
}
 
/**
 * Register a Hibernate interceptor with the current thread.
 * <p>
 * Every Session opened is opened with this interceptor after
 * registration. Has no effect if the current Session of the
 * thread is already open, effective on next close()/getSession().
 */
public static void registerInterceptor(Interceptor interceptor) {
threadInterceptor.set(interceptor);
}
 
private static Interceptor getInterceptor() {
Interceptor interceptor =
(Interceptor) threadInterceptor.get();
return interceptor;
}

}

Now when I call on the jsp page the first time I get:

exception
 
javax.servlet.ServletException
org.apache.jasper.runtime.PageContextImpl.doHandlePageException(PageContextImpl.java:845)
org.apache.jasper.runtime.PageContextImpl.handlePageException(PageContextImpl.java:778)
org.apache.jsp.jsp.accOptions_jsp._jspService(org.apache.jsp.jsp.accOptions_jsp:146)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:99)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:325)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:295)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:245)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
 
root cause
 
java.lang.ExceptionInInitializerError
com.frontier.hibernate.HibernateUtil.<clinit>(HibernateUtil.java:39)
com.frontier.hibernate.CustomerDAO.getCustomerList(CustomerDAO.java:195)
org.apache.jsp.jsp.accOptions_jsp._jspService(org.apache.jsp.jsp.accOptions_jsp:80)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:99)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:325)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:295)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:245)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)

When I refresh that same page i get same exception but different root cause:

root cause
 
java.lang.NoClassDefFoundError
com.frontier.hibernate.CustomerDAO.getCustomerList(CustomerDAO.java:195)
org.apache.jsp.jsp.accOptions_jsp._jspService(org.apache.jsp.jsp.accOptions_jsp:80)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:99)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:325)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:295)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:245)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)

I've googled around, found things about classpaths, libraries and such but as far as I can see all is well.
I've got hibernate2.jar AND cglib-full-2.0.1.jar in my WEB-INF/lib.
In my java files I'm referering to the right classes (otherwise Eclipse would warn me about it), so I'm frustrated out of idea's!

Can anyone help me?
O yeah, using JDK 1.5, Tomcat 5.5.4 and Eclipse/MyEclipse.

Another thing. The first rootcause with line 39 is from the throw/catch at wanting to build a SessionFactory and the second one at CustomerDAO:195 is at the List method at trying to get the HibernateUtil.getSession
[ December 22, 2004: Message edited by: Ritchie Warsi ]

[Mark Spritzler]

NoClassDefFoundError occur because of the class not being in the classpath. Now, Eclipse has the correct classpath. Just because Eclipse doesn't have the problem, doesn't mean that Tomcat has the same classpath. Where in Tomcat do you put your Business object?

Mark

[Ritchie Warsi]

Hi Mark, by Business Object what file do you mean/should I look for. You see, I don't know all the terms yet
If you mean my CustomerDAO, it's in my webapps/msl2/WEB-INF/classes/*package name directory structure*

[Mark Spritzler]

Originally posted by Ritchie Warsi:
Hi Mark, by Business Object what file do you mean/should I look for. You see, I don't know all the terms yet
If you mean my CustomerDAO, it's in my webapps/msl2/WEB-INF/classes/*package name directory structure*

Yes, by business object I mean your object that is causing the NoClassDefFoundError. which means based on the stack trace the CustomerDAO object.

Just out of curiosity, does this class need to be in a jar file in the WEB-INF/classes directory? I don't think so, but it has been a while for me creating any kind of Web App. Not that I did much of it before anyway.

Good Luck

Mark

[Ritchie Warsi]

Allright I still got this same problem. I restarted the whole project, but the problem remains.
The linenumbers in de stacktrace in the first lines all point out (in the end) to either a get or create session method in my HibernateUtil (see my previous post also). So I'm almost beginning to think that that's the problem.
BUT, I use that same HibernateUtil on a different project, developed under the same circumstances and same tools and showing the data list there works fine!

So pleeeeaasssee someone help me out here!