when i launch a singleplayer game it crashes and on multiplayer it can't connect and it says java.lang.NullPointerException: group

when i launch a singleplayer game it crashes and on multiplayer it can't connect and it says java.lang.NullPointerException: group

i was playing normally until i installed the new version of java. the game said it might run faster with the new version and now i can't play
please help i payed 20 euro for it. :/