Some features added in Java 8

1. What’s New in Java 8
Lambda, Default Methods, and Streams

2. What’s New in Java 8
● Lambda Expression
● Default Methods
● Streams
● Optional
● Nashorn
● New Date and Time API
● No More PermGen

3. What’s New in Java 8
● Lambda Expression
● Default Methods
● Streams
● Optional
● Nashorn
● New Date and Time API
● No More PermGen

4. Java 9 has been scheduled for general
availability in 2017

5. Lambda Expression and Method Reference

6. Lambda Expression
A lambda expression is like syntactic sugar for
an anonymous class with one method

7. Lambda Expression - Syntax
() -> body
parameter -> body
(parameters) -> body

8. Lambda Expression - Syntax Example
() -> { System.out.println(“Hello”); }
(int i) -> System.out.println(i)
(double d1, double d2) -> Double.compare(d1, d2)

9. Lambda Expression - Method References
A method references is the shorthand syntax
for a lambda expression that executes just one
method

10. Lambda Expression - Method References
Sometimes lambda expression is just a call to some method
list.forEach(s -> System.out.println(s));

11. Lambda Expression - Method References
You can turn that lambda expression into method reference
list.forEach(System.out::println);

12. Lambda Expression - Method References
Consumer<String> consumer = (s) -> {
System.out.println(s)
};
Consumer<String> consumer = System.out::println;

13. Default Methods

14. Default Methods
Default methods enable you to add new
functionality to the interfaces of your libraries
and ensure binary compatibility with code
written for older versions of those interfaces.

15. Default Methods - Example
public interface Iterable<T> {
Iterator<T> iterator();
default void forEach(Consumer<? super T> action) {
Objects.requireNonNull(action);
for (T t : this) { action.accept(t); }
}
default Spliterator<T> spliterator() { ... }
}

16. Static Methods
You can define static methods in interfaces!

17. Static Methods - Example
public interface Vertx extends Measured {
static Vertx vertx() {
return factory.vertx();
}
...
VertxFactory factory =
ServiceHelper.loadFactory(VertxFactory.class);
}

18. Static Methods - Example
Vertx vertx = Vertx.vertx();

19. Static Methods - Example
Vertx vertx =
Vertx.vertx();

20. Streams

21. Streams
A sequence of elements supporting sequential
and parallel aggregate operations.

22. Streams - Example
int sum = widgets.stream()
.filter(w -> w.getColor() == RED)
.mapToInt(w -> w.getWeight())
.sum();

23. Streams - Example
int sum = widgets.parallelStream()
.filter(w -> w.getColor() == RED)
.mapToInt(w -> w.getWeight())
.sum();

24. ?

25. Thank You