[Advanced-java] code change impact analysis tool

[Mahesh Nair]

Hi folks,

I am trying to create a Imapct analysis tool for java. 

The basic functionality of this will be to find out which other parts of my
system (granularity could be packages or Classes) is affected by a code
change (normally small  bug fixes) that i have made.  The idea is to then do
some focussed testing on those affected modules before  pushing the code on
to production. 

what i am looking for is something similar to "Find Usage" functionality
provided by most java IDEs. I want to make this more automated . The input
wil be a diff file giving the diffrence between the old and new file. what i
want is to figure out the method  which has changed and then check all the
classes in my project to find out where all that particular method is
called.

First is there a similar tool available on the net for evaluation purpose?

Second what broad approach can i use if i need to make a tool like this .
Parsing through all my classs files seems complicated and time consuming. is
there anyother way to go ?

How can i figure out what other classes use one particular class (to narrow
down the search) ?

Hope some of you can gimme pointers on the general direction i could take

tia
Mahesh