You need to hard reset your phone
First switch off your phone and then press power button+ volume up button+ home button simultaneously for 5 seconds and the android robot appears.
Then go to clear chache partition and click on power button ( it will not delete your personal data) and reboot your phone.
You will notice less lag and for battery you need to set minimum brightness while playing game.This is the response of samsung through mail for the query of latest update. @, we would like to inform you that we do not have any official confirmation regarding the next software update for the same device ‘Samsung Galaxy J 2 in India. We have noted down this feedback any update in this regard will be conveyed to you through various means of commu