Many years have passed and we have witnessed some truly amazing Batman movies over this time period and we all aware of the fact that Alfred is on Batman's side But could this possibly be true?. How is joker always successfull in getting inside batman's head and how is he always aware of batman's next move?. So many questions go answered with arrivals and declines of batman movies. Let shed some light over a couple possibilities.
Joker and Batman were close as kids.
this can also be a way for joker to know or to be aware of the way that bruce thinks.
Alfred and joker are Allies.
There is a possibility that alfred was jealous of Mr. Wayne and his wealth and wanted martha wayne for himself and was plotting to kill them but they died and left bruce wayne for him to handle.Alfred is now jealous of bruce too and doesn't want him to succeed so he meets joker in secrecy to inform him of Batman's plans.
whatever the truth is behind the Criminal mastermind of Joker it will be pretty awesome if some of his origins are explained in SUICIDE SQUAQ which come out in 2016