The generalized syntax for a generic interface : Generic Interfaces « Generics « Java Tutorial

1. Java Tutorial
2. Generics
3. Generic Interfaces

1. type-param-list is a comma-separated list of type parameters.
2. When a generic interface is implemented, you must specify the type arguments

interface interface-name<type-param-list> { // ...

class class-name<type-param-list>
           implements interface-name<type-param-list> {