Hibernate is LGPL 2.1. Here is our public statement http://www.hibernate.org/356.html As long as your code is compliant with the LGPL 2.1, you're fine. -- Emmanuel Bernard http://in.relation.to/Bloggers/Emmanuel | http://blog.emmanuelbernard.com | http://twitter.com/emmanuelbernard Hibernate Search in Action (http://is.gd/Dl1) On Jul 24, 2008, at 21:33, Oliver Plohmann wrote: > Hello, > > I already posted this question to a hibernate forum but didn't > receive any answer. That's why I saw no way round posting to this > mailing list. > > I'm working on a mapping tool that maps Java objects to RFCs. This is > somewhat similar to mapping Java objects to relational database > tables (though much simpler). I therefore got the idea to use the > hibernate hbm.xml mapping syntax for this Java-to-RFC mapping tool, > because there is no point in re-inventing the wheel and many many > people know hibernate and will therefore quickly feel at home when > using this Java-to-RFC mapping tool if it uses the same mapping XML > syntax as hibernate. > > My question is now whether also this hbm.xml mapping syntax is > completely free and may be used for another purpose than hibernate > itself or whether permission has to be granted by the authors of > hibernate. I just want to be really sure before I start, because > changing the mapping syntax in the middle of the race is a lot of work. > > Thanks in advance, Oliver Plohmann > > _______________________________________________ > hibernate-dev mailing list > hibernate-dev(a)lists.jboss.org > https://lists.jboss.org/mailman/listinfo/hibernate-dev

Its an interesting question as I have never really considered the implications of the LGPL in terms of DTD. The DTD is in fact covered under the terms of the LGPL as are all parts of Hibernate. AFAIK, referencing the DTD in your XML document(s) should constitute what the LGPL terms dynamic binding. As such, your application(s) should be fine to use whatever licensing scheme you choose if the XML doc(s) reference the *unmodified* Hibernate DTD. However, if you were to modify the Hibernate DTD you would be creating a derivative work under the language of the LGPL and your entire app/library would come under the terms of the LGPL. Again, this is *my understanding*. IANAL I am asking a lawyer skilled in this area for confirmation... - Steve Ebersole Project Lead http://hibernate.org steve(a)hibernate.org Principal Software Engineer JBoss, a division of Red Hat http://jboss.com http://redhat.com steve.ebersole(a)jboss.com steve.ebersole(a)redhat.com On Sun, 2008-07-27 at 11:58 +0200, Oliver Plohmann wrote: > Hi Emmanuel, > > thanks for your reply. I read through the hibernate license before > posting to this newsgroup in order not to bother people unnecessarily. > Problem is that it only talks about redistribution of code and code > changes. It does not say anything about interface definitions like the > XML definition in the hbm.xml files. If the hibernate XML interface > definition were nothing but a pure interface ("serves only to connect > systems") there would be no problem since interfaces used in that sense > are not protected by copyright law (contain no intellecutal effort and > are therefore not worthy of copyright protection). But these XML > definitions expose some intellectual effort (e.g. how to map 1:n, m:n, > ... relationships etc.) that goes beyond a bare interface only made to > connect systems and therefore seems worthy of protection by copyright > law. So the issue is tricky. I might have to invent my own mapping > syntax just to be sure not to break some license statement ... But I'm > still hoping for some somewhat official statement whether the hbm.xml > sytax definition is part of the Hibernate license or not :-). > > Regards, Oliver Plohmann > > Emmanuel Bernard wrote: > >> Hibernate is LGPL 2.1. >> Here is our public statement >> http://www.hibernate.org/356.html >> >> As long as your code is compliant with the LGPL 2.1, you're fine. >> >> -- >> Emmanuel Bernard >> http://in.relation.to/Bloggers/Emmanuel | >> http://blog.emmanuelbernard.com | http://twitter.com/emmanuelbernard >> Hibernate Search in Action (http://is.gd/Dl1) >> >> On Jul 24, 2008, at 21:33, Oliver Plohmann wrote: >> >> >>> Hello, >>> >>> I already posted this question to a hibernate forum but didn't >>> receive any answer. That's why I saw no way round posting to this >>> mailing list. >>> >>> I'm working on a mapping tool that maps Java objects to RFCs. This is >>> somewhat similar to mapping Java objects to relational database >>> tables (though much simpler). I therefore got the idea to use the >>> hibernate hbm.xml mapping syntax for this Java-to-RFC mapping tool, >>> because there is no point in re-inventing the wheel and many many >>> people know hibernate and will therefore quickly feel at home when >>> using this Java-to-RFC mapping tool if it uses the same mapping XML >>> syntax as hibernate. >>> >>> My question is now whether also this hbm.xml mapping syntax is >>> completely free and may be used for another purpose than hibernate >>> itself or whether permission has to be granted by the authors of >>> hibernate. I just want to be really sure before I start, because >>> changing the mapping syntax in the middle of the race is a lot of work. >>> >>> Thanks in advance, Oliver Plohmann >>> >>> _______________________________________________ >>> hibernate-dev mailing list >>> hibernate-dev(a)lists.jboss.org >>> https://lists.jboss.org/mailman/listinfo/hibernate-dev >>> >>

Anyway, it is starting to get annoying ... ;-). My conclusion I draw out of this is that it would make sense to define some basic DSL using XML to describe relationships between entities. This DSL would be free in the same way that UML is free.