I had a scheduled update on 1st February, which seems, finally, to have fixed the problem. The version number is J330FNXXU3BRL1 / J330FNO2U3BRK3 / J330FNXXU3BRI3 . It would be interesting to know whether anyone who has got that version is still getting the problem.
I had the same update on 14th January, so far my phone hasn't restarted once since the update so it must have fixed the issue.
My samsung j3 keeps restarting since 2018 and its really annoying somebody can help me?
Sorry, I just saw that you are in trouble. I have a little experience with this problem and I hope it will be useful to you: you need to make sure your phone is not suffering from hardware damage. In the absence of hardware damage, like this: charging, updating firmware, erasing the cache partition, starting safe mode, factory reset. If these methods are not able to solve the continuous restart problem, you may still have to take it to the repair shop.