Based on the example javahjni that comes with NonStop Java in the demo subdirectory and the native-maven-plugin, I've put together a build framework for exposing Guardian proc calls (in 'C') from NSJ6
http://luckyphil.github.com/nonstop-jni/
Java on NonStop isn't everyone's cup of tea, but if you are using Java and need something like the 48 bit timestamp, this should make the process easier; you do need to install maven in OSS and you need to be able to connect out to either a local repository manager (eg: nexus, artifactory or archiva) or to the internet based maven repos - maven does support proxy configuration if your NonStop can route via one.