The two have nothing to do with each other.

Jini is a specification and architecture for building distributed systems or implementing service oriented architectures that is heavily based on Java.

.NET is a sammelsurium of specifications and techologies including:

• a common language specification that allows in process cooperation of modules written in different languages
  
• a large class library similar to rt.jar
  
• SOAP and WebService bindings (which everyone seams to focus on when discussing .NET)
  
• some new programming languages like C# and J# (which is most certainly not Java)
  
• a JVM-like virtual machine called CLR
  

I would compare .NET to Java, because both of them are platforms for building and deploying applications.

Alex

.NET is a service development and deployment platform. It is similar to J2EE platform in Java Speak.

Jini is a dynamic distributed architecture for building "dynamic service networks" or "service communities". These communities can have services developed using any service platform such as .net, J2EE, CORBA.

For more information on the differences between these technologies or to know as how to integrate a .net service within a Jini community look at the recently published book "Jini Technology - An Overview" by "S. Ilango Kumaran".

Here is the amazon link
http://www.amazon.com/exec/obidos/ASIN/0130333859/qid=1007924989/sr=8-1/ref=sr_8_1_1/002-1111932-4023204

Hope this helps!

the .NET is basically a platform made to counter J2EE/CORBA. It provides much of the funtionality like transactional components and integration of XML/SOAP like its counterparts.

However JINI, though built on a JAVA platform is a new programming paradigm in distributed computing. It elevates distributed computing to a new level where programs(called "services") can host itself and be automatically discovered and then used by "clients". Clients can also look for services based on "proximity" of services on the network. This community forming and discovering feature is added by the JINI spec.

However JINI relies on the JAVA feature to safely download and execute a code remotely.