Question

It might be a noob question but I am learning java and I came across an interface which had its definition like :

public interface MyClass <T extends Comparable<T>>

Can someone please explain what does it mean? I mean what kind of interface is created.

Answer 1

It means that the generic type argument must implement the Comparable interface.

When specifying <T extends Comparable<T>> you can use e.g. Collections.sort in this interface on type T. Without extends you can not guarantee that T is comparable.

Numbers and String are e.g. comparable and implement the Comparable interface.