Why doesn’t it cause compilation errors? Integer and String are different types. And if it doesn’t matter, why do things like <T, R> exist (if one letter can stand for any number of different types, you can just type <T> , I figure)?
Integer and String are different types, but both are objects (unlike int and char),
so for <T, R> each of T and R can be a specified type of object.
You couldn’t use <S> instead of <T,R> because S would be one object, whereas <T,R> would be 2 objects. (Although you could make a class that contains two objects as instance variables, so you could make an object that holds other objects for <S> ).
1 Like