How do you package your bundles? Do you use FAB or the Maven bundle plugin etc?
If you type: headers nnn in the shell, where nn is the bundle id, then you can see the packages that bundle import|export etc. You would need to have the groovy packages as imports on the bundle that calls the service (B). So the groovy classes is visible on the classpath.
I am using the bnd plugin, and yes, I had made sure - as I noted in the original post - that running the "packages" command on the bundle confirms that all the necessary groovy.* packages are present.
I actually got it to work by adding the following directive to the Maven "bnd" plugin instructions:
I found that suggestion buried in some year-plus-old forum - as a work-around for a known issue in camel-groovy in OSGi. I am using camel-groovy v2.10.2 in Karaf, and apparently the issue still exists. It really needs to be documented better because I'm sure people waste countless hours on stuff like that.