The generics feature was introduced into Java in version 5. To start with an example, our Sortable interface until now was this:
package packt.java9.by.example.ch03; public interface SortableCollection { Object get(int i); int size(); }
After introducing generics, it will be as follows:
package packt.java9.by.example.ch03; public interface SortableCollection<E> { E get(int i); int size(); }
The E identifier denotes a type. It can be any type. It says that a class is a sortable collection if it implements the interface, namely the two methods— size and get. The get method should return something that is of type E, whatever E is. This may not make too much sense up until now, but you will soon get the point. After all, generics ...
