Have a look into the Testing/Java directory for examples of java programs using the GNUstep core libraries. Some of the examples from there will now be also made available here.

No. JIGS requires JNI 1.2, mainly because it uses weak references, which are provided by JNI 1.2 but not by JNI 1.1. There are no current plans to port JIGS to JNI 1.1.

Yes! That is a well-tested scenario. Here are a few hints: you need to make sure that:

1. your java servlet has the classpath set so that it can access the java classes you want to use. Usually, this means the System and Local Libraries/Java directories, which by default at /usr/GNUstep/System/Library/Libraries/Java and /usr/GNUstep/Local/Library/Libraries/Java . So, you need to make sure these two directories are in your CLASSPATH. If GNUstep is installed somewhere else, these directories might be somewhere else (for example, /usr/lib/GNUstep/Libraries/Java and /usr/local/lib/GNUstep/Libraries/Java are common on Unix).
2. your java servlet has the linker/library path set so that it can load in the gnustep libraries. The easiest way to do this is to add /usr/GNUstep/System/Library/Libraries and /usr/GNUstep/Local/Library/Libraries to your linker path (eg, /etc/ld.so.conf under GNU/Linux), or source GNUstep.sh before you start Tomcat.
3. the NSLog output of your java servlets goes into httpsd_error_log.