Starting a new JDO project with an Exception...

Posted on 08/06/2009 by Charalampos Chrysikopoulos

I thought it would be a nice way to kill some time, by making a mini project in google app engine using JDO. I made my model bean, made it persistent, I wrote a repository for it, and then I thought lets give it a try... The result was the following exception:

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javax.jdo.JDOUserException: You have either specified for this PMF to use a "persistence-unit" of "transactions-optional" (yet this doesnt exist!) or you called JDOHelper.getPersistenceManagerFactory with "transactions-optional" as the name of a properties file (and this doesnt exist in the CLASSPATH)
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This is strange, because I use the google plug-in for eclipse and my project is set up for GWT 1.6 + App engine 1.2 by the google plug-in, which creates automaticaly a file in META_INF directory named jdoconfig.xml. In this file is the persistance manager factory defined with the name "transactions-optional". Why can't the web-app find the file?

Seems that the problem was the non included xml file which configures jdo in the application. Look also at this post.