Interesting...
So basically you're looking for a software/services/processes execution and reload in RAM to have the same (or similar) status as after booting up, and/or possibly emulating (as it were) the overall shutdown then start-up process, instead of doing a full power down and boot cycle?
As far as I know this isn't available in vanilla Android, so you would likely need to be running a modified version and/or app on a rooted device, or have a device that comes with this kind of functionality already built-in.
That aside, I'm not sure why you would need this kind of functionality for general use, as newer Android devices (especially ones running vanilla Android) are largely able to maintain their performance and functionality without needing a restart.