Step1 : A calls B with startActivity(intent).
Step2 : B calls serviceConnector to send event to the service process and finish itself. It has no UI. It is set as Theme.NoDisplay.
Step3 : Service callbacks init C if not exist yet and C handle service responses event.
Step4 : In one case, C calls B with startActivity(intent)
Step5 : B calls serviceConnection to send event. No UI. C will onPause and when B finsih itself, C onResume()
Step6: Service callbacks and found C already exist, no create new one. C handle service respsonses.
Step7: user click button on C Fragement activity, C calls finish itself, But only C got onPause(). C couldn't be finish, no onStop(), no onDestroy() is called.