Cannot open a simple Session !

syp74s · **Joined:** Tue Jun 29, 2004 7:49 am **Posts:** 3

I followed the Hibernate tutorial (with the Cat) but got an error when i open a Session.

Here is the Servlet I use to test Hibernate :

package test;

import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;

import net.sf.hibernate.*;
import java.sql.*;
import javax.sql.*;
import javax.naming.*;

public class HibernateServlet extends HttpServlet {
private static final String CONTENT_TYPE = "text/html";

//Initialize global variables
public void init() throws ServletException {
}

//Process the HTTP Get request
public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
response.setContentType(CONTENT_TYPE);
PrintWriter out = response.getWriter();
out.println("<html>");
out.println("<head><title>hibernateServlet</title></head>");
out.println("<body bgcolor=\"#ffffff\">");
out.println("<p>The servlet has received a GET. This is the reply.</p>");
out.println("</body></html>");

/* try {
Context initContext = new InitialContext();
DataSource ds = (DataSource) initContext.lookup("java:/comp/env/jdbc/dm");
Connection conn = ds.getConnection();
Statement stmt = conn.createStatement();
stmt.execute("insert into CAT values('1', 'Felix', 'M', 10)");
conn.commit();
conn.close();
}
catch (Exception e) {
e.printStackTrace();
}
*/
try {
Session session = HibernateUtil.currentSession();

Transaction tx = session.beginTransaction();

Cat princess = new Cat();
princess.setName("Princess");
princess.setSex('F');
princess.setWeight(7.4f);

session.save(princess);
tx.commit();
}
catch (HibernateException he) {
he.printStackTrace();
}
finally {
try { HibernateUtil.closeSession(); } catch (HibernateException he) { }
}
}

//Clean up resources
public void destroy() {
}
}

As you can see the DataSource has been tested and the Database access is ok. But when I want to use Hibernate through the HibernateUtil.currentSession() call I got the following exception :

StandardWrapperValve[hibernateServlet]: Servlet.service() for servlet hibernateServlet threw exception

javax.servlet.ServletException: Servlet execution threw an exception

javax.servlet.ServletException: Servlet execution threw an exception

at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:269)

at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:193)

at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:243)

at org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.java:566)

at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:472)

at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:943)

at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:190)

at org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.java:566)

at org.apache.catalina.valves.CertificatesValve.invoke(CertificatesValve.java:246)

at org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.java:564)

at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:472)

at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:943)

at org.apache.catalina.core.StandardContext.invoke(StandardContext.java:2347)

at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:180)

at org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.java:566)

at org.apache.catalina.valves.ErrorDispatcherValve.invoke(ErrorDispatcherValve.java:170)

at org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.java:564)

at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:170)

at org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.java:564)

at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:472)

at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:943)

at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:174)

at org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.java:566)

at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:472)

at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:943)

at org.apache.catalina.connector.http.HttpProcessor.process(HttpProcessor.java:1027)

at org.apache.catalina.connector.http.HttpProcessor.run(HttpProcessor.java:1125)

at java.lang.Thread.run(Thread.java:534)

Which I think has nothing to do with Hibernate !
When debugging the HibernateUtil class :

package test;

import net.sf.hibernate.*;
import net.sf.hibernate.cfg.*;

public class HibernateUtil {
private static final SessionFactory sessionFactory;

static {
try {
// Create the SessionFactory
sessionFactory = new Configuration().configure().buildSessionFactory();
}
catch (HibernateException ex) {
throw new RuntimeException("Configuration problem: " + ex.getMessage(), ex);
}
}

public static final ThreadLocal session = new ThreadLocal();

public static Session currentSession() throws HibernateException {
Session s = (Session)session.get();
// Open a new Session, if this Thread has none yet
if (s == null) {
s = sessionFactory.openSession();
session.set(s);
}
return s;
}

public static void closeSession() throws HibernateException {
Session s = (Session)session.get();
session.set(null);
if (s != null)
s.close();
}
}

The static block is executed perfectly but the instruction that throws an exception is the one in red ! But what is strange is that I don't manage to catch the HibernateException not even the Exception (I tested it) !

Here is my hibernate.cfg.xml file :

<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE hibernate-configuration PUBLIC "-//Hibernate/Hibernate Configuration DTD//EN"
"http://hibernate.sourceforge.net/hibernate-configuration-2.0.dtd">
<hibernate-configuration>
<session-factory>
<property name="connection.datasource">java:comp/env/jdbc/dm</property>
<property name="show_sql">false</property>
<property name="dialect">net.sf.hibernate.dialect.OracleDialect</property>

<mapping resource="Cat.hbm.xml"/>
</session-factory>
</hibernate-configuration>

and the output of Hibernate :

- Hibernate 2.1.4

- hibernate.properties not found

- using CGLIB reflection optimizer

- configuring from resource: /hibernate.cfg.xml

- Configuration resource: /hibernate.cfg.xml

- Mapping resource: Cat.hbm.xml

- Mapping class: test.Cat -> CAT

- Configured SessionFactory: null

- processing one-to-many association mappings

- processing one-to-one association property references

- processing foreign key constraints

- Using dialect: net.sf.hibernate.dialect.Oracle9Dialect

- Use outer join fetching: true

- JNDI InitialContext properties:{}

- Using datasource: java:comp/env/jdbc/dm

- No TransactionManagerLookup configured (in JTA environment, use of process level read-write cache is not recommended)

- Use scrollable result sets: true

- Use JDBC3 getGeneratedKeys(): false

- Optimize cache for minimal puts: false

- Query language substitutions: {}

- cache provider: net.sf.ehcache.hibernate.Provider

- instantiating and configuring caches

- building session factory

- no JNDI name configured

I'm using the following tools :
Hibernate 2.1.4
JDK 1.4.2
Oracle 9i
Tomcat 4.0.6
JBuilderX

I would appreciate the help of the Hibernate community members

christian · **Posted:** Tue Jun 29, 2004 8:52 am

Code:

static { 
try { 
// Create the SessionFactory 
sessionFactory = new Configuration().configure().buildSessionFactory(); 
} 
catch (HibernateException ex) { 
throw new RuntimeException("Configuration problem: " + ex.getMessage(), ex); 
} 
} 

Replace the "catch (HibernateException ex)" with "catch (Throwable ex)" and log the exception. Then, throw a ExceptionInInitializerError() instead of a RuntimeException. The code in the current tutorial (you copied that) swallows exceptions.
[/code]

syp74s · **Joined:** Tue Jun 29, 2004 7:49 am **Posts:** 3

Thanks for your quick response but after replacing what you told me, the error is still there. Here is my code :

Code:

  static {
    try {
      // Create the SessionFactory
[color=red]      sessionFactory = new Configuration().configure().buildSessionFactory();[/color]    }
    catch (Throwable ex) {
      ex.printStackTrace();
      throw new ExceptionInInitializerError(ex);
    }
  }

When debbuging, the call to the line in red works fine and do not throw any exception, it is the call to sessionFactory.openSession() that throws "something" that I cannot catch in my call :

Code:

    try {
      Session session = HibernateUtil.currentSession();
      
      Transaction tx = session.beginTransaction();
      
      Cat princess = new Cat();
      princess.setName("Princess");
      princess.setSex('F');
      princess.setWeight(7.4f);
      
      session.save(princess);
      tx.commit();
    }
    catch (Exception he) {
      System.out.println("Hello");
      he.printStackTrace();
    }

christian · **Posted:** Tue Jun 29, 2004 9:24 am

You have a nested exception (probably a missing library or something) that stops the static initializer. You haven't shown this exception yet, only the Servlet exception wrapper. The code you have is fine.

syp74s · **Joined:** Tue Jun 29, 2004 7:49 am **Posts:** 3

Thanks a lot, I finnaly made it work !
I was missing only one library : jta.jar, but in your lib/Readme.txt it is written that this file is needed only on standalone applications. And since I'm running Tomcat I hadn't included it.
The reason is maybe that I'm using the Tomcat version bundled with JBuilderX : Tomcat 4.0.6 LE which comes witout without jta.jar !
One last question :
Do I need to copy this jta.jar in my WEB-INF/lib directory when going on my production server (WebLogic 8.1) or is this a jar that should already be in the server classpath ?

Again thank you for all and of course I'll send you a congratulation message if Hibernate suits my needs and more ;-) which I'm almost sure !

christian · **Posted:** Tue Jun 29, 2004 11:02 am

Weblogic has JTA, I'm sure.