How are Java generics different from C++ templates? Why can't I use int as a parameter?

Question

I am trying to create

ArrayList myList = new ArrayList();

in Java but that does not work.

Can someone explain

Answer 1

You can't use primitives as type parameters in Java. Java's generics worth through type erasure, meaning that the compiler checks that you're using the types as you've defined them, but upon compilation, everything is treated as an Object. Since int and other primitives aren't Objects, they can't be used. Instead, use Integer.