Learn Java Programming - Interface: Default Methods Tutorial
Prior to Java 8, the biggest issue with interfaces was a complete lack of scalability. Scalability allows an application to evolve and grow over time without breaking existing code. It is a concept that is learned mostly through experience. With a pre-Java 8 interface you had just about one chance to get your interface right and that was it. Once your interface was in production it became almost impossible to make a change or addition that didn't have major ripple effects.
In my Introduction to Interfaces tutorial I created two separate classes that implemented the same Engine interface, a Boeing787 and a Honda Accord. Let's suppose that I wanted to add a new abstract method called getHorsePower(), what would happen to the implementing classes? The next time I compiled both the 787 and the Accord classes, I would receive an error about an abstract method that I did not override. If I wanted to compile my code, and I do, I will have no choice but to override the new method. In the real world – if my interface was distributed and in production – I would have a bunch of very angry programmers knocking on my door.
The default method solves this issue and provides us with a new capability that did not exist before. Unlike an abstract method, a default method has a method body and it can execute statements and return values. A default method is similar to a regular class method only with the default keyword applied. I'm thinking that an interface is starting to look much more like an abstract class now ... interesting.
En esta página del sitio puede ver el video en línea Learn Java Programming - Interface: Default Methods Tutorial de Duración hora minuto segunda en buena calidad , que subió el usuario Daniel Ross 20 agosto 2015, comparta el enlace con amigos y conocidos, en youtube este video ya ha sido visto 658 veces y le gustó 5 a los espectadores. Disfruta viendo!
