Hail to the guys of the OpenNTF Domino API!
They heard the calls from us (the community) and also put that wonderful wrapper API into a OSGi plugin nutshell, so deployment of this is now really simple and by means you don't need to copy anything onto your clients and/or servers anymore!
There is a restriction in the usage of the API that way instead of deploying the JAR manually: it works only for XPages usage of the API, not for Java agents!
Just download the M4 from here: http://www.openntf.org/internal/home.nsf/project.xsp?action=openDocument&name=OpenNTF%20Domino%20API
Extract everything and the ZIP called "org.openntf.domino.xsp.update.zip" inside into another folder. Then add the site.xml into your Updatesite NSF. To get a general idea of how to use an Updatesite to deploy your plugins just read this: http://www-10.lotus.com/ldd/ddwiki.nsf/xpAPIViewer.xsp?lookupName=XPages+Extensibility+API#action=openDocument&res_title=XPages_Extension_Library_Deployment&content=apicontent
This is yet another great contribution from the OpenNTF community members! Congrats, guys! Keep up the great work!
I recently found an issue in the M4/OSGi version: https://github.com/OpenNTF/org.openntf.domino/issues/82