Classpath tools : jcfind and JWhich

JavaDeep understanding of Java classpath is something that is too often neglected. I won’t write an article about classpath, internet is full of readings about it :

Here come JWhich and jcfind. Both are classpath reflection tools.

JWhich provides a command line interface and a Java api where jcfind only has command line interface and is written in python.

I prefer to use jcfind from the command line because it’s really faster than Which4j and the command line is more practical. In Java software, I use the JWhich API that is really easy to use. The big drawback of using Which4j from command line is that you must provide a full class name, using it’s API you can search for a class simple name.


Glassfish, Hibernate and WebServices – WSGEN Classpath

Java XMLFollowing my quick and dirty how-to about using hibernate in glassfish I came across a small pitfall when dealing with metro webservices.

The glassfish’s wsgen classpath on Glassfish is not by domain, ie. the wsgen tool is not run in the domain class-loader.

When trying to deploy a webservice that returns an entity with a hibernate annotation, I got this following error :

Deploy error

Server logs showed the following trace :

        warning: Cannot find annotation method 'value()' in type 'org.hibernate.annotations.Fetch':
        class file for org.hibernate.annotations.Fetch not found
Problem encountered during annotation processing;
see stacktrace below for more information.
        ...... SNIP ......
error: compilation failed, errors should have been reported
Exception occured in J2EEC Phase
com.sun.enterprise.deployment.backend.IASDeploymentException: WSGEN FAILED
        at com.sun.enterprise.webservice.WsUtil.genWSInfo(

Adding the hibernate-annotations.jar file in the glassfish main lib/ directory added the necessary classes to the wsgen classpath.

Unit test JPA Entities with in-memory database

HibernateStill about Hibernate, I have several JPA Entities grouped in a Persistence Unit that I need to test. So here is another quick and dirty howto titled “Unit test JPA Entities with in-memory database”.

Here I assume you already have written your entities java classes with correct annotations.

As I’m working with embedded Derby for a year, I first tried with it but procton (thank you procton) pointed me to another lightweight RDBMS.

So, in this how-to we will set up a unit-tests dedicated persistence unit and use HSQLDB as in-memory database for unit tests.

UPDATE: now that Apache Derby provide an in memory backend, I implemented the very same thing with it in a new post : Unit test JPA Entities with in-memory Derby/JavaDB

Continue reading “Unit test JPA Entities with in-memory database”

Building an EJB3 app using GlassFish v2, Maven2 and NetBeans 6

In an article explicitly titled Building an EJB 3.0 application using GlassFish v2, Apache Maven 2 and NetBeans IDE 6.0, Jacek Laskowski explain in detail how Netbeans 6 can be used by maven users willing to use GlassFish as an EJB3 container.

I’m currently doing these type of things with Netbeans 6 but I didn’t know it was feasible with so few command line maven invocations.

Quick and dirty howto : Use Hibernate in Glassfish V2


As Leon pointed in comments, it’s not a good idea to put the hibernate jars in the app server classpath like in this post. Hibernate community had published a howto explaining how to use Hibernate in Glassfish but the link has expired. Here is a copy from google cache:

To use hibernate with glassfish, all you have to do is put hibernate and its dependencies into your EAR file. This might also with with a WAR file.

In your persistence.xml, specify hibernate using this tag:


You can also specify hibernate properties as usual, for example:

<properties>  <property name=”” value=”none”/></properties></blockquote>





For my first post here I’ll write a quick and dirty howto for using Hibernate inside the Glassfish V2 container.

  1. Download Hibernate projects
  2. Put’em in the domain’s lib dir
  3. Change your persistence.xml file
  4. Enjoy :)

Details are following :
Continue reading “Quick and dirty howto : Use Hibernate in Glassfish V2”