Code Monkeyism

Programming is hard by Stephan Schmidt

Grails, Hibernate and JPA: hanging application

When developing an application in Grails I’ve been adding a backend written for JPA. This should be no problem - you think. But while the unit test for the JPA backend work fine for themselves, when adding the backend to the Grails application, Grails hangs when accessing the EntityManager. It does not help that all my efforts to join the Grails mailing list with my gmail address have failed so far. I have no clue how to fix this problem which took most time out of my last weekend :-) Perhaps Hibernate does not like to act as a Grails ORM and at the same time as a JPA provider. Or I have JAR conflicts. Any ideas?

Update: It has been suggested that the problem might be that there are several incompatible ASM jars in the classpath.

About the author: Stephan Schmidt is currently a team manager at ImmobilienScout24 in Berlin. Stephan has been working as a head of development and CTO. He has used a lot of different technologies in the last 20 years including Java, Rails and Python. Stephans main field of interest is maintainablity and productivity in software development. Want to know more? All views are only his own.

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Comments

I’ve had problems in the past mixing Spring 2.0, Hibernate 3.x, and JPA. The problem usually comes down to the “asm.jar” file, which is normally included in both the Hibernate library and the Spring 2.0 library. Unfortunately, each includes a different version, and the conflict breaks the application.

I do remember seeing a post on one of email lists you mentioned about a similar conflict. Grails is built on top of both Spring and Hibernate, so maybe that’s not surprising.

By the way, if you can’t get into the email lists directly, both are archived at Nabble:

http://www.nabble.com/codehaus—Groovy-f11866.html for Groovy, and
http://www.nabble.com/grails—user-f11861.html for Grails.

Good luck,

Ken Kousen

My blog is at http://kousenit.wordpress.com

stephan

Thanks Ken, I’ll take a look there, and perhaps try to remove one asm.jar from the classpath.

you can post to those forums: http://www.nabble.com/codehaus—grails-f11860.html

stephan

@Ray: Thanks, I’ll try that approach.

[...] As I wrote before, using Java JPA in my Grails application, the Grails application (0.6) hanged. After not much help from the mailing list, I updated to Grails RC1.0 without success. Adding the newest Hibernate JARs and Annotations JARs to the grails/lib directory solved my issue though. Grails no happily uses my JPA/Dao backend. Puh. Bookmark at:StumbleUpon | Digg | Del.icio.us | Dzone | Newsvine | Spurl | Simpy | Furl | Reddit | Yahoo! MyWeb [...]

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