SeniorSoftwareEngineer,SeunghwanLee_이승환 Details
Senior Software Engineer
Seunghwan Lee
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.
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.
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
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.
Class Details
25 Class 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.
Create 9 backend fundamentals with Stream.
- 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
Practice with 12 advanced Stream exercises.
- 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
Practice with 4 design pattern exercises using Functional Programming.
- 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.

Software Engineer
Seunghwan Lee
[Current]
Software Engineer
at LinkedIn (Sunnyvale, California)
Recognizable
Projects & Awards
[Former]
2013 ~2015
Software
Development Engineer
at Microsoft (Sunnyvale, California)
2012
Software Engineer Intern
at Facebook (Menlo Park, California)
2011
Software
Developer Intern
at Groupon Korea (Seoul)
[Education]
Bachelor: Carnegie Mellon University BA / Computer Science and Mathematics (double degree)
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Curriculum
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
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 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.
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.
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.
Required Programs
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.
