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From David Blevins <>
Subject Re: Problems deploying EJBs in embedded Tomcat OpenEJB
Date Thu, 19 Nov 2009 04:38:48 GMT
This is fantastic feedback!  A project couldn't hope for better.

Thank you so much for taking the time to write all this.  I had a good  
laugh on your #4 as I've totally done that myself -- and you're right,  
sometimes it works.

I'm neck deep in a new feature right now, but hopefully can find time  
to update some of the docs.

If you're interested we could arrange to give you direct access to the  
docs (a wiki) pretty easily and you could edit as you see fit.  You  
clearly have the perfect mindset for this kind of thing.  I'd be happy  
to IRC or Skype with you to get the info across and you just need to  
write it.  Realize you're still evaluating, but throwing it out there  

Glad things are working now!


On Nov 18, 2009, at 3:10 PM, freeway wrote:

> Thanks very much for your prompt and helpful reply.  After enabling  
> Tomcat
> logging, we received enough information about the problems to debug  
> our
> configuration.  OpenEJB now appears to be working with our webapp,
> supporting the legacy EJBs without issues.
> To answer your question about documentation, here is a summary of the
> information sources I used with some suggestions.
> 1. I started by following the tomcat.html page instructions, which in
> hindsight was correct but still incomplete and unsatisfactory.  The  
> EJBs did
> not load during initial testing, and there was no reference here to
> troubleshooting or logging.  The title 'Installation for the  
> Impatient'
> raised my hopes that somewhere there was a longer and more explicit
> procedure for the patient, but apparently there is not.
> 2. After reading the rest of the product documentation at the web  
> site, I
> tried to use the configuring-logging-in-tests.html page, but it is  
> written
> to apply to the stand-alone rather than the embedded environment,  
> with no
> reference to the latter.  As I was not familiar with Tomcat's native  
> logging
> at the time, it did not help.
> 3. I searched the openejb webapp's files, and found the following  
> pages:
> howitworks.html, ejbclasses.html, ejbref.html, enc-help.html, re- 
> help.html.
> They seemed very helpful in that they described some potential  
> issues, use
> of the Tomcat classloaders, and so on; but I gather that they  
> pertain to
> older releases and are now obsolete.
> 4. In increasing desperation, I searched your SVN repository as well  
> as the
> web in general for more information of any kind about the workings of
> OpenEJB-inside-Tomcat.  In most cases, the pages I found were marked  
> as
> obsolete, but that did not stop me.  Very often obsolete  
> documentation still
> contains much useful information, particularly when no other  
> information
> sources are available, and the package and environment as a whole is  
> new and
> unknown.  I assumed that my primary problem was an incorrect/ 
> incomplete
> configuration, and the old web pages showed examples that seemed very
> relevant, even if some of the details might have changed.
> Overall, I would suggest the following.
> 1. Update/organize all of your documentation to explicitly  
> distinguish the
> stand-alone from the embedded installation, to avoid mix-ups.
> 2. Provide more references and links to relevant details about  
> Tomcat, where
> applicable (for example, logging).
> 3. Provide a technical overview that describes what the openejb webapp
> actually does within the Tomcat environment, and how it uses or  
> interacts
> with Tomcat's features.  This is important, because I don't think  
> that most
> users of projects like OpenEJB want a complete 'black-box'  
> solution.  They
> want at least some understanding of how it behaves within their target
> environment in order to have some idea of how to handle problems,  
> particular
> when that environment is shared with applications and other external  
> code.
> The openejb webapp clearly uses the Tomcat environment in a very non- 
> typical
> way, introspecting the other webapps to find their EJBs, and so on.   
> Without
> at least a high-level understanding of how it works, it is very easy  
> for a
> user to fear the impact that OpenEJB might have on a shared Tomcat
> environment, to blame it for other unrelated problems, and generally  
> to let
> our paranoia regarding unknown software get the best of us.
> 4. Provide at least one working example webapp with older, un- 
> annotated EJB
> source code.  Seeing such an example might have reassured me that the
> recommended approach is corrected, and would have prevented me from
> introducing unnecessary/harmful configuration.
> Again, thanks for your help.  I will continue to post OpenEJB
> points/questions of interest to this forum.
> David Blevins wrote:
>> I think this might be a case of doing too much.  If we can retrace
>> your steps and find the sources of information you used, we should be
>> able remove or update them.
>> The only steps required are the four steps listed here:
>> On Nov 13, 2009, at 9:37 AM, freeway wrote:
>>> All the EJB classes are
>>> packaged in a single JAR file that is part of the webapp.  The code
>>> is not
>>> written with injection or any annotations, and I am defining the EJB
>>> objects
>>> to the webapp entirely using the XML files WEB-INF/web.xml,
>>> META-INF/context.xml, META-INF/ejb-jar.xml, and
>>> $CATALINA-HOME/conf/openejb.xml.
>> Put the ejb-jar.xml in the jar where your ejbs live just like you
>> would if the war was an ear file.
>> In the future this won't be required, but it is currently.
>>> Here is the relevant EJB reference from the webapp's web.xml.
>>>     <ejb-ref>
>>>       <ejb-ref-name>lsbpm/LsBpmEjbFrontDesk</ejb-ref-name>
>>>       <ejb-ref-type>Session</ejb-ref-type>
>>>       <home>com.oakgrovesystems.reactor.frontDesk.EJBFrontDeskHome</
>>> home>
>>>       <remote>com.oakgrovesystems.reactor.frontDesk.EJBFrontDesk</
>>> remote>
>>>     </ejb-ref>
>> Good.
>>> Here is the relevant EJB configuration element from context.xml.
>>>  <Ejb name="lsbpm/LsBpmEjbFrontDesk" auth="Container" type="Session"
>>>    home="com.oakgrovesystems.reactor.frontDesk.EJBFrontDeskHome"
>>>    remote="com.oakgrovesystems.reactor.frontDesk.EJBFrontDesk"
>>>    factory="org.openejb.client.TomcatEjbFactory"
>>> openejb
>>> .naming
>>> .factory
>>> .initial="org.apache.openejb.client.LocalInitialContextFactory"
>>>    openejb.ejb-link="lsbpm/LsBpmEjbFrontDesk"/>
>> This will cause problems and should be removed.  We will actually do
>> all this kind of work for you automatically.
>> We've tried to prevent people from doing this by wiping it from out
>> documentation leaving only a "do not use this" page:
>> If you can let us know where you saw this, we can try and get it
>> updated.
>>> Here is (I think) the relevant configuration from a much longer ejb-
>>> jar.xml.
>>> <ejb-jar id="LsBpmEjb_jar">
>>> ...
>>> <enterprise-beans>
>>>   <session id="LsBpmEjbFrontDesk">
>>>     <ejb-name>lsbpm/LsBpmEjbFrontDesk</ejb-name>
>>>     <home>com.oakgrovesystems.reactor.frontDesk.EJBFrontDeskHome</
>>> home>
>>>     <remote>com.oakgrovesystems.reactor.frontDesk.EJBFrontDesk</
>>> remote>
>>> <ejb-class>com.oakgrovesystems.reactor.frontDesk.EJBFrontDeskBean</
>>> ejb-class>
>>>     <session-type>Stateless</session-type>
>>>     <transaction-type>Container</transaction-type>
>>>     ...
>>>   </session>
>>> ...
>>> </enterprise-beans>
>>> ...
>>> <ejb-jar>
>> Looks good.
>>> Here is the loader servlet definition from the openejb webapp, which
>>> I did
>>> not think was necessary but added nonetheless for testing purposes
>>> based on
>>> some documentation that I found.
>> Adding that will cause problems and it should be removed from your
>> webapp.  If you can point us at the documentation you found that
>> recommended, we can definitely update it.
>>> The EJB JAR file, which contains a META-INF/ejb-jar.xml file, is
>>> saved in
>>> the directory ${catalina.base}/lsbpm/openejb/apps/.  I also left a
>>> copy in
>>> the WEB-INF/lib/ directory of my webapp.
>> Having the jar file in the WEB-INF/lib/ should be all you need.
>>> Finally, the $CATALINA_HOME/conf/openejb.xml file has not been
>>> modified, and
>>> contains a Deployments element at the bottom referencing the EJB
>>> directory
>>> location.
>>> <Deployments dir="apps/" />
>> All relative directories in the openejb.xml are resolved relative to
>> openejb.base, which in Tomcat will be the same as catalina.base.  So
>> you could put apps in ${catalina.base}/apps/.  Though really it's far
>> more convenient to just include everything needed in the webapp.
>>> The Tomcat stdout log entries on startup are as follows.
>>> OpenEJB init-params:
>>> 	param-name: openejb.home, param-value: C:\Program Files\Apache
>>> Software
>>> Foundation\Tomcat 6.0/lsbpm/openejb
>>> 	param-name: openejb.loader, param-value: LsBpmServer-webapp
>>> log4j:WARN No appenders could be found for logger (OpenEJB.options).
>>> log4j:WARN Please initialize the log4j system properly.
>>> Apache OpenEJB 3.1.2    build: 20091010-03:11
>>> context path = /LsBpmServer
>>> context path = /openejb
>>> ...
>> The output above will go away once you remove the LoaderServlet and
>> let the openejb.war do all the loading.  As well any issues with  
>> beans
>> not loading *should* go away.
>>> I have been unable to increase the OpenEJB
>>> log level by overriding the file with my
>>> own
>>> file as described in the OpenEJB documentation.
>> Looks like we need to be more explicit and I can see where this
>> confusion could come from.  Using OpenEJB in another server like
>> Tomcat or Geronimo or as a standalone server is very different than
>> embedding OpenEJB in a plain Java SE environment using the JNDI
>> InitialContext.
>> For Tomcat, the logging configuration should be automatically added  
>> to
>> ${catalina.home}/conf/
>> I hope this helps.  Thank you for providing such a complete email.   
>> It
>> definitely gives us some better on what issues we need to steer  
>> people
>> away from and how to better define the Tomcat/OpenEJB path.
>> -David
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