Learn how easy it is to sync an existing GitHub or Google Code repo to a SourceForge project! See Demo
You said you checked the FAQ, but did you try searching the archives at
http://www.mingw.org? When I searched for jni, the very first hit was
entitled "Re: Java, JNI, DLL and underscore decorations". See if
http://sourceforge.net/mailarchive/message.php?msg_id=4112301 or any of the
other messages helps.
Tired of spam? Get advanced junk mail protection with MSN 8.