How to link the Javadoc of a Library in Eclipse?

What (legal) workarounds are there for Eclipse Public License and GPL incompatibility?

• The Free Software Foundation considers the Eclipse Public License (EPL) and the GPL to be incompatible. Based on my reading of their reasoning, it would seem that the LGPL would be similarly affected -- IANAL, please correct me if that reading is incorrect. Now, there is a guide for the copyright holder of the GPL-ed code to provide exceptions allowing for the code to be linked against GPL-incompatible libraries, but it'd still preclude linking to GPL-ed code from others (if the code is already linked against an EPL library), and the situation with linking a GPL-ed program against an EPL and another LGPL library seems unclear. I'd like to know the answer to several questions: What exactly is the restriction against linking a GPL-ed product against both an EPL library and an LGPL library? Is it not allowed without the LGPL copyright holder's explicit permission, as it would be with GPL, or is it allowed? Would an exception granted by the EPL copyright holder be sufficient? Such an exception was considered safe by Trolltech (now part of Nokia), when it used to license the Qt library using its own Qt Public License which is GPL-incompatible; and by the KDE project, whose libraries link against Qt and are released under the LGPL, while KDE apps are generally released under the GPL. The FSF's objection is due to "weak copyleft" and "choice of law clause" -- the former seems unobjectionable, if the EPL license holder grants an exception, but what sort of exception granted by the EPL copyright holder would satisfy the "choice of law clause" objection? Thanks in advance.

• Answer:

  I am not going to answer your specific question or give advice for your specific case, but here are some general concepts: The FSF does say that the EPL is GPL-incompatible.  That doesn't mean it is not fixable. "Weak copyleft" often means that the right to close the source is given (the GPL does not grant the right to close the source). If there is a combination of software, some of which is licensed to you only under the GPL and some of which is licensed to you only under the EPL, then you only have a license to distribute it in a way that is compatible with both licenses.  If a recipient of the combined software from you wants Canadian law to apply, they can't have that because the EPL says that U.S. law is to apply.  So, there is a constraint that isn't part of the GPL that was added and added constraints are not allowed under the GPL. However, if the EPL license holder grants an additional license, in the form of an exception to the EPL - call it the EPL-X license, you would then have the rights to distribute the EPL-ed code under the GPL because the EPL-X license grants you that right.  The EPL-X license might paraphrase as "I grant you the rights to the code under the EPL, but if you want, you can do your distribution using a license like the EPL with the choice of law clause removed or just go ahead a license your combined code using the GPL, we are fine with that."  That's how incompatible FOSS licenses are often dealt with where you have cooperation of one or both licensors.  The GPL licensor might also be the one to grant an additional license, one that says "go ahead and combine with some EPL code, I don't really mind."