If your time is in a variable called t
int hours = t / 60; //since both are ints, you get an int
int minutes = t % 60;
System.out.printf("%d:%02d", hours, minutes);
It couldn’t get easier
Addendum from 2021:
Please notice that this answer is about the literal meaning of the question: how to convert an amount of minute to hours + minutes. It has nothing to do with time, time zones, AM/PM…
If you need better control about this kind of stuff, i.e. you’re dealing with moments in time and not just an amount of minutes and hours, see Basil Bourque’s answer below.