It's recommended that you fork the repository into your own.
Before contributing any code, please file an issue first! The issue ID shall be used as part of the topic branch name that you work on.
Work on a topic branch, with the branch name composed of the Issue ID and something descriptive, such as 11-android-support
Assuming you have a forked upstream, make sure you've defined the upstream as one of the remotes:
$ git remote add upstream git://github.com/infinispan/infinispan.git
You should now be able to fetch and pull changes from upstream into your local repository, though you should make sure you have no uncommitted changes:
$ git fetch upstream
$ git fetch upstream --tags
$ git checkout master
$ git pull upstream master
$ git push origin master
And for each minor version branches (e.g., 1.2.x):
$ git checkout 1.2.x
$ git pull upstream 1.2.x
$ git push origin 1.2.x
The Android components require Android SDK. Be sure to set ANDROID_HOME:
$ export ANDROID_HOME=/path/to/android/sdk