This is the report of my training that i have done in summer 2008.
Jini is the open source platform for parallel computing on distributed systems.
Hadoop is the framework that Google has developed using Map-Frame on his file system GFS.
If you are looking for a framework to do parallel computing on distributed file systems and try to develop a network that repairs itself these two are really suitable for you. This is what i have done to learn their basics and comparing the functionalities of both frameworks.

Access the pdf file here