Answer:
It's a compact way of doing an if-else statement.
General Format is
<<em>condition</em>> ? <if condition is true> : <else>;
Example:
I could rewrite:
if(a==1) temp = 1;
else temp = 999;
as
temp = (a==1) ? 1 : 999;
If it stores any type of objects mixed, use Object as storage class. All classes inherit from Object and for primitives use their respective wrapper classes. Or just use one of the bazillion container classes that already exist.
