http://wiki.apache.org/hadoop/HowToContribute is the best place to start. Checking the code in through git will not trigger a jenkins build, unless you have a special setup that goes beyond Apache provides. You do not need to compile the entire tree to get Map/Reduce, but typically it is not a big deal to compile everything.
On 5/8/12 11:50 PM, "Radim Kolar" <firstname.lastname@example.org> wrote:
I am interested in working on mapreduce package, so not sure if I need
to compile the whole tree.
I work on branch-0.23. It can be just imported into SpringToolsSuite,
then click on Run -> Maven -> type in 'compile' target. It compiles
module it just fails on Avro stuff. But it is good enough that you can
edit it in Eclipse with some comfort. Then just commit to git and let
Jenkins on Unix to build it for you.