OT: Apache POI Native Library using GCJ

[TJ Mather <tjmather@maxmind.com>]

This is marked as offtopic, since it doesn't involve the RHUG project,
however I thought it may interest anyone who wanted to compile Apache
POI with GCJ...

I was able to get Apache POI to compile down to a shared library by
compiling *.java -> *.class using Ant with Sun JDK, then running
gcj -shared -o poi.so `cat classlist.txt` where the classlist contained 
the core HSSF files (not the ones that used Swing, etc)[1].  I had to 
compile FormulaParser.java, POIFSViewEngine.java, and HexRead.java to 
*.class using GCJ, because I got a "bad pc in exception_table" if I tried 
to compile the JDK *.class to *.so using GCJ.  Also note that *.java -> 
*.class using GCJ doesn't work for some *.java files.

For more details on to build and use the Apache POI GCJ shared library
see http://tjmather.com/poifilter/

-TJ