Have you considered dual-licensing ECJ? There's some standard verbiage floating about that lets the user license under A or B at the user's choice...
On Feb 17, 2011, at 12:49 PM, Sean Luke wrote:
> Peter, almost all of ECJ is distributed under the AFL 3.0, because at the time it was the best available academic open source license. We'd probably license it under Apache nowadays. The FSF (pretty controversally) has been claiming that the AFL and GPL are incompatible, basically because the AFL is better written with regard to jurisdiction clauses etc., even though one of the AFL's license grants is to replace the license. AFL's author (Lawrence Rosen) disagrees.
> Anyway, ECJ was meant to be used widely. As far as I am concerned, ECJ can be freely mingled with code of any other license, such as Weka, for whatever project you like.