如何在Android应用程序中实现双进程保护？

I found some android app contains 2 processes in background even though I quit the app. After I get into App manager.However I found it hard to kill them when I try to kill the processes. I kill the first one, the second will recreate it; I kill the second one, the first will recreate the other one. I finally manage to kill them after I restart my device. But I found the app start the processes soon. I just wanna know how it can restart itself and so hard to kill. I search the whole internet, but I can not find any related solution. Thanks in advance. I just wanna how it work not to develop these annoying apps.I found some android app contains 2 processes i