type parameter
nounUK /taɪp pəˈræmɪtə/
US /taɪp pəˈræmɪtər/
A type parameter is a placeholder name in code that you fill in with a real type later.
In the list class, T is a type parameter that can stand for any type you choose.
OTHER MEANINGS
2. In Java, a type parameter is declared in angle brackets after a class or method name.
The class Box<T> declares T as a type parameter.
3. In C++, a type parameter is often called a template parameter.
template <typename T> uses T as a type parameter.
4. A type parameter can have bounds that limit which types are allowed.
<T extends Number> restricts the type parameter T to number types.