Hi ag,
As suspected -- unresolved dependency. Remember that in Liferay 7, assuming that you are working with the new Liferay Workspaces and Gradle tools, dependency management gets a little trickier. Chances are that your dependency in your gradle script is set to a "provided" type -- like you have in Maven, where the build process will include the required library in the classpath at runtime, but won't include it in the actual bundle. Normally this is done when the library is already available, typically in the global space -- in older versions of Liferay you could compare this to, say, the portal-service.jar that was in the TOMCAT_HOME/lib/ext. It could also be that you have everything in the runtime, but you aren't exposing (exporting) something that you are trying to import somewhere else.
Is the issuetracker-service referenced in the error supposed to map to code that you have written (like a service bundle)? If yes, can you share with us a little more about your project and perhaps the bnd files?
