I just downloaded 1.1.7a (glibc) for RedHat 5.1 and it worked fine.
I had a few hassles with Kaffe before, hence the preference
for using 1.1.7a.
There are a number of projects out there using Java. I've
seen quite a few servers (one is a Java version of Apache),
ORB implementations, a few frameworks for XML serialization,
to name a few
There's lot's of stuff out there, but most of it doesn't
quite pass muster.... they're either trivial, poor quality,
or run too slowly (method invocations, class loading times
and object instantiation seem especially slow, even in JIT
VMs).