TBH I don’t know how to build a valid jar.
I followed this : Distributing bindings through the IoT Marketplace
Binary Builds from Pull Requests
Instead of manually building the jar from sources and uploading it to Github/Dropbox/GDrive or some other website for sharing, there is now a much simpler way: I have setup the PR builder on our Jenkins, which first of all validates that a PR is buildable, but secondly also deploys the result in a new Maven repo on our Artifactory instance: https://openhab.jfrog.io/openhab/libs-pullrequest-local/
So as an example, the Plugwise binding from this PR is automatically available as a jar at https://openhab.jfrog.io/openhab/libs-pullrequest-local/org/openhab/binding/org.openhab.binding.plugwise/2.1.0-SNAPSHOT/org.openhab.binding.plugwise-2.1.0-SNAPSHOT.jar . This url can be directly used as the download url for the IoT marketplace.
But I don’t know why the jar has not been built automatically 