Getting started with Java 8 – Part 2
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Functional Interface:-
You cannot use any interface with lambda expression. Only interfaces with one abstract method can be used with lambda expression. These type of interfaces are also called function interfaces.
Java 8 comes with many functional interfaces that you can use in your code.
Predicate ->
This functional interface is used to check if some condition is true or not. It has one abstract method named test that takes a value of type T and returns a
boolean. Let’s say we want to define a predicate that filters out all the even number from a list.
Predicate evenNumbers = name -> name % 2 == 0; boolean test = evenNumber.test(6);
Consumer ->
This functional interface represents an operation that accepts a single input argument and returns no result. It has a method called accept that take value of type T
and has void return type.
Consumer messageConsumer = message -> System.out.println(message); messageConsumer.apply(“message”)
Function ->
This functional interface takes one argument as input and produces a result. Let’s say we want to find the length of a string.
Function<String, Integer> numberOfLetters = s -> s.length(); Integer length = numberOfLetters.apply(“word”);
By:
Aditya Agrawal
www.coviam.com
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