Java Vienna

Joint Meetup with Scala Vienna

Agenda:
18:00 doors open
18:20 organizational stuff
18:30 - 19:30 Mill: Untapped Potential in the Java Build Tool Experience - Li Haoyi
19:30 - 19:55 Pizza break
19:55 - 20:00 Raffle
20:00 - 21:00 Vaadin 24 in the real world - building the Java Vienna Raffle! - Sebastian Kühnau

Untapped Potential in the Java Build Tool Experience
The Java language is known to be fast, safe, and easy, but Java build tools like Maven or Gradle sometimes don't quite live up to that standard. This talk will explore what "could be": where current Java build tools fall behind modern build tools in other communities, in performance, extensibility, and ease of getting started. We will end with a demonstration of an experimental build tool "Mill" that makes use of these ideas, proving out the idea that Java build tooling has the potential to be much faster, safer, and easier than it is today.

About the Speaker
Li Haoyi graduated from MIT with a degree in Computer Science and Engineering, and since then has been a major contributor to the open source community. His projects have over 10,000 stars on Github, and are downloaded over 20,000,000 times a month. Haoyi professionally built distributed backend systems, programming languages, high-performance web applications, and much more.

Vaadin 24 in the real world - building the Java Vienna Raffle
TBA

About the Speaker
Sebastian Kühnau ist seit zwei Jahrzehnten Java-Junkie und schon während seines Studiums Vaadin verfallen. Seit 2016 arbeitet er in verschiedenen Tech-Rollen bei Vaadin und unterstützt Kunden, maßgeschneiderte Webanwendungen zu entwickeln. Nebenher ist er zudem auf verschiedenen Events in und mit der Community aktiv.

About the Speaker:
Simon Gartner - Softwareentwickler @ Gepardec IT Services GmbH.
Simon ist Softwareentwickler mit viel Erfahrung mit Legacy-Code. Er beschäftigt sich in seinen Projekten intensiv mit der Anwendung von OpenRewrite in der Praxis. Sein Fokus liegt bei der automatisierten und reproduzierbaren Durchführung von Migrationen. Simon konnte mehrere Modernisierungsprojekte, wie Frameworkupgrades, effizient und innovativ meisten.

how John started to like TDD (instead of hating it)
Let me share a story about how John (a developer like any other) started to understand (and enjoy) writing Tests before the Production code.

We've all felt an inevitable "tedium" when writing tests, haven't we? If it's boring, if it's complicated or unnecessary? Isn't it? John thought so too, and, as much as he had heard about writing tests before production code, he had never managed to put it into practice, and even when he had tried, John had become even more frustrated at not understanding how to put it into practice outside of a few examples katas 🤷‍♂️

Listen to this story in which I will explain how John went from not understanding Test Driven Development (TDD) to being passionate about it... so much that now he doesn't want to work any other way 😅 ! He must have found some benefits in practising it, right? He says he has more advantages than working in any other way (e.g., you'll find defects earlier, you'll have a faster feedback loop or your code will be easier to refactor), but I'd better explain it to you in the session, right? Ah! And if you think everything will be theoretical, no! Get ready to see code examples with Spring Boot.

PS: Think of John as a random person, as if he was even the speaker of this talk 😉 !

About the Speaker
Nacho Cougil is a software engineer from Barcelona, fan of TDD and XP practices. He has been working with Java and other web technologies before the effect 2000 and had experience in different roles in the IT world now working at Dynatrace writing code to monitor applications. You may probably meet him before as founder of the Barcelona Java Users Group & the Java & JVM Barcelona Conference ( JBCNConf ). He enjoys spending time with his family, playing sports & improving his eXtreme Programming skills.
Nacho is the founder of the Barcelona Java User Group and a Java Champion.

Joint meetup with AWS Vienna Meetup !

Agenda

18:00 doors open
18:20 welcome
18:30 High performance Serverless Java on AWS - Vadym Kazulkin
19:30 Break
19:55 Raffle
20:00 How to develop, run and optimize Spring Boot 3 application on AWS Lambda - Vadym Kazulkin
21:15 Networking nearby

High performance Serverless Java on AWS
Java is for many years one of the most popular programming languages, but it used to have hard times in the Serverless community. Java is known for its high cold start times and high memory footprint, comparing to other programming languages like Node.js and Python. In this talk I'll look at the general best practices and techniques we can use to decrease memory consumption and cold start times for Java Serverless applications on AWS Lambda including GraalVM (Native Image) and AWS own offering SnapStart based on Firecracker microVM snapshot and restore and CRaC (Coordinated Restore at Checkpoint) runtime hooks. We'll also look into the SnapStart priming techniques which help us increase the Lambda performance and explore how AWS Lambda Profiler for Java can help us identify this potential. We'll also explore the impact of the SnapStart snapshot tiered low-latency cache on the cold start times.

I'll also provide Lambda functions performance (cold and warm start times) benchmarking for:

• Deployment package sizes
• Lambda memory settings
• Java compilation options
• Managing Lambda dependencies with Lambda layers
• Choice of garbage collection algorithm
• Choice of hardware architecture x86 vs arm64
• HTTP (a)synchronous clients

How to develop, run and optimize Spring Boot 3 application on AWS Lambda
In this talk I will present and compare several options of how to run Spring Boot 3 application on AWS Lambda using the following framework or tools:

• AWS Serverless Java Container
• AWS Lambda Web Adapter
• Spring Cloud Function
• Custom Docker Image.

I'll also discuss strategies how to optimize cold start of such Lambda function with AWS Custom Lambda Runtime based on GraalVM Native Image and AWS own offering SnapStart based on Firecracker microVM snapshot and restore and CRaC (Coordinated Restore at Checkpoint) runtime hooks. Moreover I'll present various (SnapStart) priming techniques to reduce the cold start even further and explain the benefits of the snapshot tiered cache. Is Spring Boot native support of CRaC also a potential optimization? I'll also discuss optimization strategies for the warm start/execution time of the Lambda function.