How can I recursively grep particular files in a directory?
Solution 1:
find . -name '*.java' | xargs grep <your pattern here>
Solution 2:
There is a tool specially designed for this type of need: ack.
ack is a tool like grep, aimed at programmers with large trees of heterogeneous source code
Also read the "Top 10 reasons to use ack instead of grep." at the ack page.