A generic type can accept parameters.
A generic type is often called a parameterized type.
You pass reference types in angle brackets to generic types.
List myList;
E is called a type variable, namely a variable that will be replaced by a type.
A generic type that uses a type variable E allows you to pass E when declaring or instantiating the generic type.
If E is a class, you may also pass a subclass of E
If E is an interface, you may also pass a class that implements E.
By convention, you use a single uppercase letter for type variable names.