To use this APK do something like:

1) Build your favorite AOSP flavor.
2) Start an emulator:
    $ emulator
3) Push over hellod binary:
    $ adb remount && adb sync
4) Install the Java client:
    $ adb install -r <path-to-APK-in-out-directory>
5) Put selinux in permissive mode.
6) Start hellod:
    $ adb shell "(hellod ) </dev/null >/dev/null 2>&1 &"
7) Start Java client:
    $ adb shell am start -S -a android.intent.action.MAIN \
                           -n "android.aidl.tests/.TestServiceClient"
8) Watch output on logcat:
    $ adb logcat -s TestServiceClient hellod