Forking a LGPL Library for a commercial application

Question

I am planning to use Snowball stemming solution in one of my commercial application.There is also a utility to generate the Java code for the snow ball stemmers. Apparently the default code is not optimized & I found that MG4J (http://mg4j.dsi.unimi.it/) has done quite improvements over it & want to use that in my application.

1. Can I use LGPL library in my commercial appplication
2. I also wanted only stemmer portion of the library as I cannot afford to include whole jar along with my application, So I need to created striped down version of jar file. Can I do that.
3. I also intend to do some modification to the code as well.

Can some one guide on the implications.

Answer 1

From what I understand with LGPL v2 is that you can use the library in commercial applications. However, any changed made to the library must be provided in source form. The library follows the standard GPL rules, but linking to it doesn't make your application GPL or LGPL.

Answer 2

Quick answers:

1. Yes, but with some caveats.
2. Yes.
3. Yes.

How to do this? Follow the Practical Guide to GPL Compliance!

Answer 3

Be very careful if you are linking LGPL libs against proprietary Java code. The FSF (authors of the L/GPL) have declared that using the import statement in Java code is considered to be linking against the library and thus creates a derivative work -- which means certain conditions apply. Do not assume that using import in Java is the same as linking against a DLL in C -- it is not. See this article.

However some copyright holders may include a "classpath exception" clause in their particular (modified!) version of the LGPL.