If I had a joint bank account and the other party died, what monies am I entitled to?

First of all, how was title to the account held? In other words, did the account list both of your names as "tenants in common" or did it list them as "joint tenants with rights of survivorship" (JTWROS)?  If it was as tenants in common, you have no rights to the deceased's share. It becomes the property of their estate and passes to beneficiaries under a Will, if there is one. If there isn't, then it will pass to the heirs according to the intestacy laws of NJ.  However, if you held the account as JTWROS, you are entitled to all money in the account.  And you are entitled immediately upon death by operation of law (i.e. automatically).