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More Java, Java 8

The features added to Java 8 are widely used in APIs provided by Java as well as third-party libraries and frameworks such as Spring. If you are a Java developer in this era, you must know them. Make them your own technology easily and quickly through this lecture.

(4.9) 329 reviews

4,390 learners

  • whiteship
Java

Reviews from Early Learners

What you will learn!

  • Learn about functional interfaces, lambdas, and method references.

  • Learn about basic and static methods in interfaces.

  • Learn about Streams and Optionals.

How to properly utilize JAVA 8
I'll show you the smartest way.

🙆🏻‍♀ In this lecture, we will learn about the major features added in Java 8.
Understand Java 8 code and write it yourself! 🙆🏻‍♂

Lecture Introduction 👨‍💻

Learn about Java 8, which was first released in March 2014 and is still the most widely used version by Java developers, more than six years later.

If you've finished learning the basics of Java, but still feel like you don't know much about it and see unfamiliar syntax when looking at code written by others , it may be because you don't fully understand the features added in Java 8 .

What can you do with Java 8? 🐔🍴

Here we have a pre-built chicken that implements an interface called Chicken.

public class KeesunChicken implements Chicken {

}

As you can see, we only implemented the interface and did not override any methods.
But this is possible.

public class App {

public static void main(String[] args) {

Chicken keesun = new KeesunChicken();

Egg egg = keesun.create();

}

}

How on earth did we come to be able to use the create() method that returns an Egg?

Now, let's look at the following code. Here's a chicken. It's tending an egg that wants to grow into a half-and-half chicken.

Chicken.takesCare(new Egg() {

@Override

public String wannaBe() {

return "half seasoned half fried";

}

});

This code can also be shortened to:

Chicken.takesCare(() -> "Half Seasoned Half Fried");

Are you wondering how we can reduce it so cleanly without even using the Egg type?

This time, let's classify eggs.

List eggs = new ArrayList<>();

eggs.add(EggWithColorAndSize.of().size(3).color("yellow"));

eggs.add(EggWithColorAndSize.of().size(4).color("white"));

eggs.add(EggWithColorAndSize.of().size(3).color("white"));

eggs.add(EggWithColorAndSize.of().size(5).color("yellow"));

eggs.add(EggWithColorAndSize.of().size(3).color("brown"));

eggs.add(EggWithColorAndSize.of().size(4).color("yellow"));

Among the eggs shown here, let's select only the yellow eggs, sort them by size, and then print the egg's wannaBe.
After taking this course, you will be able to write and understand code like this:

eggs.stream().filter(e -> e.getColor().equals("yellow"))

.sorted(Comparator.comparingInt(EggWithColorAndSize::getSize))

.map(EggWithColorAndSize::wannaBe)

.forEach(System.out::println);

You can also understand and write code like the following, which runs the egg-laying task in a separate thread and then enjoys the egg (with a callback) when it's laid:

CompletableFuture future = CompletableFuture.supplyAsync(() -> {

System.out.println("Kkokio~ Kkokkokko~ " + Thread.currentThread().getName());

return EggWithColorAndSize.of().size(5).color("white");

}).thenAccept((egg) -> {

System.out.println("Yum yum yum: " + egg.wannaBe());

});


future.get();

There are many other interesting contents provided by Java 8, such as Date and Time API, changes in annotations, and changes in memory areas, so please take the class.

thank you

Recommended for
these people

Who is this course right for?

  • Developers or students who have completed basic Java programming training

  • Developers or students who want to learn the key features of Java 8

Need to know before starting?

  • Java Programming Fundamentals

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네이버와 아마존을 거쳐 현재 Microsoft에서 시니어 소프트웨어 엔지니어로 일하고 있습니다.

아인슈타인은 "교육이란 사실을 가르치는 것이 아니라, 생각할 수 있는 힘을 기르는 것이다."라고 말했습니다. 그리고 저도 그 말에 깊이 공감하며 강의를 만들고 있습니다.

유튜브:
'백기선' 채널에서 개발자 고민 상담 및 개발자에게 유용한 지식 공유
번역: 스프링 및 하이버네이트 관련 서적 다수 번역
저술: 쉽게 따라하는 자바 웹 개발

Curriculum

All

23 lectures ∙ (4hr 56min)

Course Materials:

Lecture resources
Published: 
Last updated: 

Reviews

All

329 reviews

4.9

329 reviews

  • namuhuchutong6966님의 프로필 이미지
    namuhuchutong6966

    Reviews 3

    Average Rating 4.3

    3

    100% enrolled

    "More like a live coding class than a lecture" Most people have probably taken classes from professional instructors or teachers. It is hard to expect well-organized class progress, abundant materials, etc. from this lecture. However, I think it is a good lecture for those who can acquire it by thinking about the topic, researching it, and doing it themselves. I was able to allocate additional time because I am a student, but I think busy people might not like the lecture progress. However, the lecture you uploaded recently seems to have improved this problem. Since it is an old lecture, please take this into consideration when choosing it.

    • mycatisrockstar님의 프로필 이미지
      mycatisrockstar

      Reviews 9

      Average Rating 5.0

      5

      43% enrolled

      It is no exaggeration to say that I came to like Java thanks to this lecture. In particular, Mr. Ki-seon is the first person who explained streams and functional interfaces so easily. Thanks to him, I, who always gave up on coding tests in Java without even trying, ended up studying coding tests in Java. There is some feedback that it feels insincere, but I liked Mr. Ki-seon's indifferent tone, as if Java doesn't need to be difficult, because it relieved the burden I had about Java. After listening to this, I also bought Effective Java 1, 2 and Code Manipulation!! Thank you, King God General Mr. Ki-seon. Thank you 🥹🥹

      • enni님의 프로필 이미지
        enni

        Reviews 26

        Average Rating 5.0

        5

        100% enrolled

        I hesitated to pay for the course because of some reviews, but it seems that many people are satisfied when they are taught like an elementary school.. I have often felt that Ki-seon is a bit unfriendly when it comes to answering questions, but his voice is always nice during the lectures, and although he doesn't start the lectures perfectly prepared, I think that even elite developers working at Microsoft go to the lectures like this, so I think that even that is something to learn. I also think that just because there is a lot of content doesn't mean it's good. Sometimes, there are lectures that are extremely long compared to the price, but when you listen to them, they usually extend the lecture time by 20 or 30 minutes even though they could have explained it in 5 minutes like Ki-seon.. I haven't been able to listen to many of Ki-seon's lectures yet because I don't have time, but from what I've heard so far, I think they are all satisfactory for the price. If you want to see a lecture that teaches like an elementary school student, look at something else, but if you really want to learn the essentials quickly, I recommend Ki-seon's lectures. Everything I've listened to was good.

        • cco24160663님의 프로필 이미지
          cco24160663

          Reviews 3

          Average Rating 4.7

          4

          100% enrolled

          It was a good opportunity to think about JAVA8 again. I think it was good to have a process of getting used to it by showing and chewing on the new features one by one. Rather than deleting and writing content in one class when writing code, I think it would be a more perfect lecture if you create a package for each class and proceed.

          • zito님의 프로필 이미지
            zito

            Reviews 6

            Average Rating 5.0

            5

            100% enrolled

            I have been using Java for many years, but I am not familiar with the grammar after Java 8 and have only used the existing grammar. Thanks to this lecture, I was able to learn new grammar and functions, and I think my perspective has broadened. Thank you :)

            • whiteship
              Instructor

              Thank you for your feedback. The functions covered in this lecture will be the basic functions that you will use in Java in the future. Thank you for your feedback.

          $42.90

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