Why my phone reboot or shutdown itself

thanks for your quick reply, i already replaced the battery and reset the phone i also flash new stock rom via odin but the problem is the same :(

first i do a factory reset then the phone work just fine for 6 hours and the problem back again

then i flash the stock rom (sammobiles) the phone work fine for while and the same problem back again

Hmm...... so even if you would do a reset, the problem remains right?

I guess that you are running version Jelly Bean version 4.2.2.

Please take a look at the battery information screen and look at the running processes, is there anything that stands out? Like for example heavy usage google services or something.

Normally the screen should have the most usage and after that Android OS itself.

There should be something inside your phone which is causing that issue, since you already replaced the battery.

As for the battery, is it an original samsung battery?

yes android version is 4.2.2 , i already check battery information, actely after flashing i have not installed any app even i don't setup the google service the battery is original from a local samsung store, i am really confusing because i can't see if that a software or hardware problem :(

Hmm..... okay, try and wipe your cache partition.

Maybe there are still some remnants of the previous os which could cause problems.

It won't hurt to try, since there's nothing to lose at this moment.

When that's done, observe your phone for at least 24 hours.

How old is your phone btw?

thanks a lot, i already try that, i have the phone at least half year now