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.

Sean


On Feb 17, 2011, at 12:27 PM, Peter Mueller wrote:

> Hi,
>
> I have a question about ECJ.
>
> I am a PhD student in CS and doing research in Machine Learning and  
> use Weka extensively, both as a library in my programs as well as  
> extending my own classes from it. Weka is licensed under GPL2+.
>
> Do you allow the usage of ECL in the same project as a GPL2+ (in  
> this case, Weka), as long as the AFL 3.0 (and the GPL2+) is obeyed?
>
> If I publish a paper at a conference and reference that both ECL and  
> Weka classes are extended/used in my project, is this legal?
>
> I am not really sure about this and would like to get a clearer  
> picture.
>
> Thanks in advance
> Peter Mueller
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