•primitive (int, boolean,
...)
–just eight of them, built into
language
–names are Java keywords
–in box-and-arrow pictures,
values are in the box
•reference (Bank, Terminal,
...)
–these are the objects in
OOP
–names are the names of
classes
–there are as many classes as you
care to invent
–some come shipped with Java (String, …)
–in box-and-arrow pictures,
values are arrows (references) in the box