jconf-2024-workshop-with-josh-long.md

Java Conference (JConf) Workshop - Josh Long

Github repository - https://github.com/joshlong-attic/2024-bootiful-spring-workshop

Key Topics from Workshop

Tools and Development Environment

• IDE choices: IntelliJ, VSCode, Eclipse.
• Java: GraalVM (team working on it as part of Oracle).
• Key Resources:
  • start.spring.io: An API, website, and IDE wizard for bootstrapping Spring applications.
  • Devtools: For instant changes during development.
  • Docker Compose: Automates container setup.
  • Testcontainers: Helps with automated testing/dev setup.
• Amazon Corretto: Mentioned as a widely used Java distribution.

Development Best Practices

• Spring JavaFormat Plugin:
  • Ensures consistent formatting across teams.
  • GitHub Repository.
  • Note: Still not formatted automatically.
• Environment Variables:
  • SDKMAN:
    • sdk env init.
    • SDKMAN RC.
    • IntelliJ plugin.
  • direnv: For managing environment variables.
• Password Management: 1Password/Bitwarden have an API tool for secrets management.
• Desk check: Ensuring consistent experience for all developers.

Core Concepts and Programming in Java 21+

• Data-Oriented Programming: Examples in Java 21+.
• Dependency Injection & Beans:
  • Stereotypes (from UML, describes component function).
  • Bean lifecycle.
  • BeanPostProcessor (BPP).
  • Transaction demarcation.
  • AOP (Aspect-Oriented Programming):
    • Proxy: method point, adds callback to methods.
  • Spring Boot uses BeanPostProcessor to wrap beans.

Advanced Spring Features

• GraalVM and AOT (Ahead of Time) Compilation:
  • Installing and using GraalVM.
  • Building native images with GraalVM for optimized performance.
  • Managing AOT lifecycles in Spring.
  • Tree-shaking: Optimization by removing unused code (like shaking a tree to remove dead branches). However, it can inadvertently discard necessary code.
  • Challenges with serialization/deserialization: GraalVM only preserves types that are passed as parameters or return types, meaning some features (like serialization) may be discarded.
  • Manual hints: Need to add hints manually to preserve the necessary code, either through JSON configuration or by referring to Oracle documentation.
• Spring Batch Processing:
  • Loading data from CSV files to SQL databases.

Data Management

• JdbcClient for database interactions.
• SQL initialization.
• Flyway for database migrations.
• Spring Data JDBC for simpler persistence management.

Web Development and APIs

• REST Services:
  • RestClient vs RestTemplate (RestClient is newer and preferred; RestTemplate is older and considered legacy).
  • Declarative clients.
• Creating REST controllers (including functional style).
• GraphQL: Alternative to REST for querying APIs.

Messaging and Integration

• Event-Driven Architecture:
  • Messaging technologies like RabbitMQ and Apache Kafka.
• Spring Integration: Leveraging file-based events to trigger application events.
• Event Sourcing:
  • Storing and replaying events to rebuild system state.
  • Spring helps with this, and I believe Spring Batch is involved. However, other components like Spring Cloud Stream or Spring Data may also play a role.
  • Ensures consistent event handling and fault tolerance.

Scalability and Multithreading

• Non-blocking IO: Improves scalability by handling requests asynchronously.
• Virtual Threads (Project Loom) vs Carrier Threads:
  • Virtual Threads provide lightweight, efficient threading.
• Demos from José Paumard and Cora Iberkleid showed examples of virtual thread scalability.
• "Hey" load testing tool for simulating traffic.

Architecting for Modularity

• Spring Modulith: Building modular monolithic applications with Spring.
• Externalized Configuration: Managing configurations separately from the application code.
• Testing:
  • ArchUnit for architecture tests.
  • Port 0: Random Port in Spring Boot for testing purposes.

Artificial Intelligence and Spring

• Spring AI:
  • Basics of integrating AI models with Spring.
  • Using ChatClient for AI-driven conversations.
• Retrieval-Augmented Generation (RAG): A technique used in AI for augmenting queries with relevant data.
• LLAMA: Mentioned as a local AI model option.

Microservices

• Centralized Configuration: Managing configurations across microservices.
• API Gateways: Deciding between reactive and non-reactive API gateways.
• Event Bus: Enables refreshable configuration, service registration, and discovery.

Security

While not covered in detail during the workshop, Josh recommended watching the following video:

• "Passkeys: Goodbye Passwords, Hello Security! (SpringOne)"

Key concepts mentioned in passing:

• Authentication and Authorization.
• OAuth:
  • Spring Authorization Server.
  • OAuth clients and resource servers.
• Protecting messaging code.

Additional Notes & Personal Takeaways

• Language Servers: Many language servers, one editor. Can be used with VSCode, VIM, others...
• "Tuples" in Java: Need to learn more...
• Identity of Record: "The identity of a record is the identity of the component (constructor)" – a principle mentioned.
• Resident Size: Mentioned, but further details were not provided.

Q&A Approach

Josh's philosophy during the Q&A session:

• "I may not know, but I probably know who does know..."

TODO: Add RSS as a tool to measure memory usage