Last year Java 9 launched with tons of new features. In this blog post, I’m going to explain streams in Optional (introduced in Java8). Now you can get streams to form Optional which I think is a good feature.
Below example shows how to get a stream from Optional in Java 8 & Java 9.
package com.jbisht.blogs.java9.usingoptional; import java.util.Optional; import java.util.stream.Stream; public class OptionalDemo { public static void main(String[] args) { // Java 9 style getPerson().stream() .map(Person::getName) .map("Java 9 "::concat) .forEach(System.out::println); getEmptyPerson().stream() .map(Person::getName) .map("Java 9 "::concat) .forEach(System.out::println); // Java 8 Style getPerson() .map(Stream::of).orElseGet(Stream::empty) .map(Person::getName) .map("Java 8 - "::concat) .forEach(System.out::println); } private static Optional<Person> getEmptyPerson() { return Optional.empty(); } private static Optional<Person> getPerson() { return Optional.of(new Person("JITENDRA SINGH")); } static class Person { private String name; public Person(String name) { this.name = name; } public String getName() { return name; } public void setName(String name) { this.name = name; } } } Happy Coding 😀😀😀 !!! If you have any feedback please comment down below.
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