下图描述从一个Application A如何bind在Application B中的Service.

The picture above is the flow chart for how the source Application bind a target service
Major includes four steps:
(1) Inform AMS to start the bind, flow chart in blue;
(2) Start the target application process once not yet created, also create the 
            Activity Thread, in Aubergine;;
(3) Create the service, in red;
(4) Bind Service and push it, in yellow.

Android bindService流程