I was looking at this message and scratching my head, because as Tony mentions, there's no explicit reference to javax.activation.DataSource. I googled around for some instances of that error, and I think that message shows up because there's a subclass of DataSource referenced, and the subclass is accessible but DataSource itself isn't. You may have an activation.jar in your Maven repo, but the kicker is that Maven won't put it on the classpath unless you call it out as a dependency! This could be a subtle Maven issue--the jasperserver lib (or something it depends on) might not be calling out a dependency, but there is something else that depends on activation.jar and things "just work". If the dependency chain changes for some reason, then all of a sudden activation.jar stops being included, and things start blowing up. To add an explicit callout for activation.jar, add the following to the <dependencies> of jasperserver-api-impl/engine/pom.xml: <dependency> <groupId>javax.activation</groupId> <artifactId>activation</artifactId> <version>1.1</version> </dependency> Hopefully, things will start working. I'll check this fix in to SVN, because it shouldn't really hurt anything.