One of my little projects at the moment is Java access to Solaris kstats, using JNI to interface with libkstat. The idea is to bring Java up to parity with perl in this respect - and the Sun::Solaris:Kstat module h(along with the associated kstat command) has been very useful, limited in that it doesn't naturally do graphics (and there are cases where a picture is worth a thousand words - or numbers).
OK, so development has been painful - I've goofed up several times in the code. And every time I goof up java dumps core on me. (Using JNI means that all the safety built into Java goes straight out the window.) But I've moved on from simple lookups to a fully fledged kstat browser: