Hi,
While irods4j is not considered stable, we recommend users begin migrating to it sooner than later.
The stability situation is mostly about the design of the public API. That is, we want to leave room for changes in case a major design issue is discovered. With that said, I don't expect there to be major changes since the library is modeled after the C/C++ libraries which are stable.
And having people use it will help catch bugs and allow us to improve the library faster.
Hope that helps!
Kory Draughn
Chief Technologist
iRODS Consortium