Video killed the Jini
Jini was pretty cool when it was announced. However, together with Sun unable to place it in a product niche combined with the heavy requirement of a JVM meant it never really took off. It looks like Sun is repositioning it as a "web service". JXTA is much better and looks like it's succeeding. Dropping the requirement of a JVM and being XML based like UPnP (copying Microsoft for a change).
It looks like UPnP will succeed in the embedded device market where Jini failed:
"Since UPnP was announced, responsibility for UPnP has moved to the UPnP Forum (www.upnp.org), which boast a large membership list of participating companies (Sony, Philips, Siemens, IBM and Pioneer to name a few - Sun was a latecomer but also joined the Forum).
Ultimately, to be successful, UPnP faces the same challenge Jini did: it needs a critical mass of devices shipping, which requires the industry to come together to create device and service specifications. This seems to be happening: On Friday the specifications by the AV working group (covering the specifications for media servers, media sinks and the transports between the two) were posted for 45 day review for forum members. Once approved, we need to start seeing AV products ship, and hopefully we will."
Author of a Jini book and almost writing a eulogy for Jini:
Whatever happened to Jini?
A paper written for the WWW2002 conference about the JXTA project Edutella: