Question

Ok, so I was reading the Java online tutorial for generics and I found this:

E - Element (used extensively by the Java Collections Framework)
K - Key
N - Number
T - Type
V - Value
S,U,V etc. - 2nd, 3rd, 4th types

I have seen a lot of methods in Java use the “E” notation but I was looking for a method that uses the “K”, key notation. Anyone can help please?

Answer 1

Theres no real need to use K, V, E, T etc in your own classes but they are nice standards.

K and V for example are used by Map. A good example of K and V is a HashMap!

HashMap<K, V> hm = new HashMap<K, V>();

And implementing:

HashMap<Integer, String> hm = new HashMap<Integer, String>();