How do Task Managers kill apps?

Question

First of all I know it\'s bad to use a task manager/killer in Android and all that, but what I was wondering is how do task managers like Advanced Task Killer k

Answer 1

slayton has good answer in this question.I add this detail to his answer:
- when you use ActivityManager.killBackgroundProcesses(PackageName) , you can not kill foreground process.

I saw these open sources project link in K_Anas'answer to this question:
- github repository
- code.google