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Mastering JAVA Stream with 25 Practical Backend Development Exercises

Senior Software Engineer, Seunghwan Lee

Class Details

SeniorSoftwareEngineer,SeunghwanLee_이승환 Details


Seunghwan Lee
Senior Software Engineer

Hello, I’m Seunghwan Lee.
I'm a Senior Software Engineer at LinkedIn,
a professional social media service acquired by
Microsoft in 2016 for a substantial amount of 30 trillion USD.

As it is famous for blitzscaling,
we were able to grow rapidly through
the New Product Development strategy that
rapidly changed and upgraded products
in a rapidly changing market.

"And behind this growth, functional programming,
which utilizes Java efficiently and flexibly, plays
a large role. Here, I would like to convey the
development methodologies using
Java Stream, which is used on LinkedIn,
to developers who want to develop
their products in an agile manner."

Since this lecture is not for beginners in Java,
I'll be showing how to use the essential
functions of user management,
and transaction management that
backend developers face in complex projects,
and code exercises using both Java Stream
and a functional programming approach.

I've included all my tips on the core technology
and methodology for scalability and reusability
to quickly evolve the software we develop and
change it into the form customers want.
I hope you will master it and increase
your future value as a developer.

Background images
Coloso Class Breakdown Details 1

Length: 56 videos
(Duration 7h 56m)
Difficulty: Intermediate
Unlimited views

Coloso Class Breakdown Details 2
Video Details

Audio: Korean
Subtitles: English

Coloso Class Breakdown Details 3
Software Required

• Eclipse 4.6 or above
• Java 8 or above

Coloso Class Breakdown Details 4

PPT and Java programming files


Class Highlights

From the Basics to Hands-on
Functional Programming

You can learn about the basics and hands-on application of functional programming, which replaces loops with a single line of code.

Coloso Seunghwan Lee Introduction

From Basics of JAVA Stream
to Advanced Application

I will show you how I code so you can master the basics and applications of JAVA Stream through the given project exercises

Coloso Seunghwan Lee Introduction

Silicon Valley
Securing backend exercise

By practicing backend development exercises such as actual member management and transaction management, you can gain insights into streams used in the field.

Coloso Seunghwan Lee Introduction

Class Details
25 Class Exercises

Master Class with 25 Practical Backend Development Exercises

If you learn Java functional programming and Java streams with only grammar, you may feel like you can easily understand it, but you will quickly reach the limit in actual use. Therefore, in this class, we will focus mainly on practicing member management and transaction management in a simple mini-exercise form, to master the basics of streams, connection, processing, mapping, filtering, and parallel processing, through the codes used by actual SNS companies.

PART 01.
Create 9 backend
fundamentals with Stream.
- Filter unverified members
- Filter order errors
- Extract email List
- Extract customer ID
- Extract emails from unverified members
- Extract customer ID with payment errors
- Extract orders with payment errors within the last 24 hours
- Sort members by name
- Sort orders by order date
PART 02.
Practice with
12 advanced Stream exercises.
- Find the number of unverified members among those who joined within the last 24 hours
- Find the largest amount of order errors
- Check if all given members are verified
- Check order error
- Find the sum of the members’ number of friends
- Find the total order amount
- Create a member object app with a member ID
- Create an order status map with order ID
- Group orders by order status
- Group orders by status and obtain the sum of the amounts for each group
- Divide into groups of members with over and below 100 friends
- Send email alarms to unverified members
PART 03.
Practice with 4 design pattern
exercises using Functional Programming.
- Creating member objects using the Builder Pattern
- Method to send email only to specific members at run time
- Verify members flexibly when creating members
Flexible payment workflow

With Functional JAVA and JAVA Stream as the upcoming trend!
Only the one who uses both JAVA Functional Programming
and JAVA Stream programs knows them the best.

Seunghwan Lee, Senior Software Engineer of LinkedIn headquarters
will provide real backend development exercises
to teach about JAVA Stream.

Background images
Coloso Seunghwan Lee
Software Engineer
Seunghwan Lee

Software Engineer
at LinkedIn (Sunnyvale, California)

Projects & Awards

2013 ~2015
Software Development Engineer
at Microsoft (Sunnyvale, California)

Software Engineer Intern
at Facebook (Menlo Park, California)

Developer Intern
at Groupon Korea (Seoul)

Bachelor: Carnegie Mellon University BA / Computer Science and Mathematics (double degree)

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In-depth Look

*Please note that the release date of the course video, the image and content of the curriculum, etc. are subject to change without notice.

Interview with
Senior Software Engineer
Seunghwan Lee

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When I was an intern at Facebook, I’ve seen developers change the lives of people around me and even around the world.

I came to America to study after graduating from high school. I studied double majors in computer science and mathematics at Carnegie Menlo. I went to the army and interned for developers at Groupon Korea for three months, and I interned as a software engineer at Facebook headquarters before graduating from college. I think my experience on Facebook at the time built the stepping stones to work as a JAVA developer at LinkedIn in the future.

I've opened my eyes to code optimization while working at Microsoft.

I started my full-time career as a programmer at Microsoft. I started as a backend developer and developed an application. In Korea, it is said that developers change into managers when they get older, but I wanted to work as a developer for a long time, so I spent a lot of time absorbing numerous know-how related to the development and the experiences of superiors. What I realized this time was that we Koreans had very good development skills and that in order to be recognized for our skills, we had to constantly strive for optimization, not just hard work. Microsoft taught me a lot, but I moved to LinkedIn to grow into a backend developer.

7 years at LinkedIn. I am a backend developer specializing in member and order management.

I used to work in a commerce team at LinkedIn, but now I work as a B2B application backend developer. When I do backend programming, I often encounter situations where I have to process a large amount of data efficiently. JAVA Stream is an essential tool for this situation. In addition, various design patterns using functional programming are also frequently featured. All of LinkedIn's engineers use JAVA Stream as a meal every day. It's also an essential part. Just as we're moved by the beautiful text as we read, I and the developers around me show each other that we're moved by the beautifully written code. Most of these codes are optimized using Functional Programming and Stream. Even older developers have a shallow understanding of Functional Programming, so they use inefficient code, and I often point that out and fix it. I think that's one of the reasons why I can tell you about JAVA Stream.

I'll help you master both functional programming and JAVA Stream using actual exercises used in the industry.

What surprised me was that even though Korean developers are very good, they don't use much functional programming or Stream unexpectedly. In Silicon Valley, you can't even work as a JAVA developer without knowing these two. And the increasingly popular Functional Programming or Stream doesn't take long to learn. Many JAVA developers say that they don't come to Silicon Valley because they can't speak English, but in fact, developers don't have to speak English well. I hope you learn Functional Programming and JAVA Stream quickly in 5 hours, challenge yourselves to go to Silicon Valley and get paid in millions.

Software Required

This course will use
• Eclipse 4.6 or above
• Java 8 or above

Please purchase and install these program(s) for an optimized lecture experience.

Java Eclipse

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