openjpa-users mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Adam Hardy <>
Subject Re: enhancement roadblock
Date Fri, 06 Feb 2009 18:12:16 GMT
I am concentrating now on getting build-time enhancement working.

I thought I'd try with the maven-antrun-plugin using the config shown (copied 
from the list here) but I get this error - the offending class is an entity 
superclass which is in the jar in the error message. Java knows exactly which 
jar it is in, yet can't find it so I guess I've missed a simple piece of the config.

    [java] Caused by: 

(No such file or directory)
      [java]     at Method)
      [java]     at<init>(
      [java]     at<init>(
      [java]     at serp.bytecode.BCClass.write(
      [java]     at 

This is the PCEnhancer launch config:

                 <path id="cp">
                   <path refid="maven.test.classpath" />
                   <path refid="maven.compile.classpath" />
                   <path refid="maven.runtime.classpath" />
                   <path refid="maven.dependency.classpath" />
                 <fileset id="enhance.path.ref" dir=".">
name="${build.outputDirectory}/org/permacode/patternrepo/domain/entity/*.class" />
                 <echo message="Enhancing classes...." />
                 <java classname="org.apache.openjpa.enhance.PCEnhancer"
                   classpathref="cp" dir="${build.outputDirectory}"
                   <arg line="-properties META-INF/persistence.xml#OpenJpaJDBC" />
                 <echo message="Enhancing classes for OpenJPA done!" />

It seems I might need to reference the entity bean in the fileset 
'enhance.path.ref' but I'm not sure how to include a jar with a class in there.

Kevin Sutter on 06/02/09 15:45, wrote:
> Hi Adam,
> You are right in your thinking not to use the "fall back" enhancement
> processing for production use.  It was meant as an easy "out of the box"
> experience for simple apps.  It was not meant for production use.  All of
> this has been documented in our forums and JIRAs (which you have already
> found).
> We are doing more investigation into the Java 6 class redefinition support.
> This doesn't seem to be 100% complete either, at least for some scenarios.
> So, the best bet (and most proven) is to stick with standard PCEnhancement.
> This can be done in several ways -- statically during build, or dynamically
> via the -javaagent approach or tied into the classloader of a suitable EJB3
> container.
> In the WebSphere environment, the classloader enhancement process is tied
> into both the EJB and Web Containers (same Java EE runtime implementation).
> But, it doesn't sound like this linkage is provided by Tomcat.  I have no
> direct experience with Tomcat -- just reading your note below.
> So, it sounds like your best approach is to do the enhancement during the
> build process.  If you are experiencing un-enhanced entities at runtime,
> then either your build-time enhancement is not working, or your packaged
> application isn't picking up the enhanced classes, or you accidentally have
> non-enhanced entities also available via your Tomcat environment.
> Because we don't want our WebSphere customers to accidentally use the "fall
> back" enhancement, we actually turn this off for OpenJPA within WebSphere.
> You can do this with this property in your persistence.xml file:
> openjpa.RuntimeUnenhancedClasses = warn
> By default, this is set to "supported".  Another value is "unsupported",
> which just detects the problem a little earlier.  By using "warn", you still
> won't fall into the "fall back" enhancement and you will get some more
> helpful messages concerning the entities that have not been enhanced.
> I don't have a specific, complete answer to your situation.  But, maybe if
> you can experiment a bit with the above information and provide some more
> details, we can help get your environment working to your expectations.
> Good luck!
> Thanks,
> Kevin
> On Fri, Feb 6, 2009 at 9:05 AM, Adam Hardy <>wrote:
>> I need to enhance the entities in my current project because otherwise with
>> 'fall-back' enhancement, the core functionality of the application cannot be
>> run, due to StackOverflowErrors (because of the large number of unenhanced
>> entities that OpenJPA has to deal with, according to JIRA and the mailing
>> list archives).
>> I'm running Java 1.6.0_12 so I think I'm right in saying that the runtime
>> enhancement used by OpenJPA on the unenhanced entities will be Java 6 class
>> retransformation - but it's causing the issue above.
>> I have tried specifying the javaagent as a JVM option, but I have some
>> problems with this in the web server. I'm using tomcat and it looks like I
>> have to put my complete webapp into tomcat shared directory so that the
>> enhancement process has the classes available at boot.
>> My entity beans have a fair amount of encapsulated business logic so there
>> are a fair number of external utility classes and jar dependencies.
>> Is there a way to configure the javaagent on a per-website basis for
>> tomcat?
>> Secondly I have configured the openjpa-maven-plugin so that it launches the
>> PCEnhancer during my maven build, but the x*?!"@ app doesn't run with the
>> build-time enhanced classes.
>> It just hangs while loading the webapp, when Spring tries to load the
>> managers (the transaction-wrapped business tier). That's both during
>> integration testing with JUnit and when deployed in tomcat.
>> I think that sums up my current situation. Can anyone suggest a way
>> forward?
>> regards
>> Adam

View raw message