User discussions are active on at  and  as well as on platforms like StackOverFlow.
The bugzilla is actively used by the community to provide bug reports, feature requests and patches.
Also on gerrit there are contributions from users in form of pull requests. An oomph setup that is also used by the committers makes it very easy to contribute.
 - https://www.eclipse.org/forums/index.php?t=thread&frm_id=27&
 - https://groups.google.com/forum/?hl=en#!forum/xtend-lang