[MM’s] Engineering Weekly #39 — Kotlin, Java and Spring
Modern JVM development is maturing fast: better Kotlin ergonomics, safer Java and a more modular Spring ecosystem.
🎯 Featured Article
🧩 Next level Kotlin support in Spring Boot 4
Spring Boot 4 significantly improves the Kotlin developer experience, aiming to make Kotlin a first-class choice for backend development.
⬢ Improve Kotlin-first APIs, documentation and samples across Spring Boot
⬢ Align framework conventions with idiomatic Kotlin
⏩ TL;DR (Quick Recap)
⬢ Strengthen Kotlin and Java ergonomics across the Spring ecosystem
⬢ Address JVM scalability and performance lessons from real-world systems
⬢ Embrace modularization, tooling updates and safer defaults in Spring Boot 4
☕ JVM Corner
⚙️ Kotlin 2.3.0 Released
The latest Kotlin release introduces new language features, performance improvements and tooling refinements.
⬢ Enable previously experimental features by default
⬢ Improve compiler, tooling and multiplatform performance
🧵 How Java Virtual Threads Broke Netflix
A real-world case study of virtual threads, thread pinning and JVM evolution from Java 21 to Java 24.
⬢ Explain how thread pinning affected large-scale production workloads
⬢ Show why newer JVM releases significantly reduce these risks
🧠 Building a Fast, Memory-Efficient Hash Table in Java
A deep dive into advanced hash table design inspired by SwissTable.
⬢ Apply modern data-structure techniques to Java
⬢ Balance performance gains with implementation complexity
📊 InfoQ Java Trends Report 2025
An overview of adoption trends across Java, Kotlin, the JVM and related frameworks.
⬢ Track how teams adopt new JVM language features
⬢ Highlight emerging patterns in tooling and runtime usage
🗞 Java News Roundup: Spring Tools 5, TornadoVM, Payara, Hibernate
A snapshot of recent releases across the Java ecosystem.
⬢ Summarize key framework and platform updates
🍃 Spring Updates
🌱 Spring JMS Client: A Complete Guide to JmsClient in Spring Boot 4
A practical guide to the new JmsClient API and when JMS is still the right choice.
⬢ Simplify JMS usage with a modern client API
🛠 Spring Tools 5.0 Released
The latest Spring Tools release focuses on API versioning, AOT and null-safety checks.
⬢ Improve IDE support for modern Spring applications
🔌 gRPC in Spring Boot
An introduction to first-class gRPC support in Spring-based applications.
⬢ Enable high-performance gRPC with Spring abstractions
⬢ Integrate gRPC cleanly into existing Spring Boot projects
🔐 Spring Security 7 Multi-Factor Authentication
A hands-on tutorial for enabling built-in MFA support in Spring Security 7.
⬢ Apply modern authentication patterns with minimal configuration
⬢ Improve baseline security beyond passwords
🧩 Create a Custom Auto-Configuration with Spring Boot
A guide to building your own Spring Boot auto-configuration modules.
⬢ Understand how conditional configuration works
📦 Spring Boot 4 Modularization: Fix Auto-Configuration Issues After Upgrading
An explanation of breaking changes caused by Spring Boot 4 modularization.
⬢ Diagnose missing features after upgrading
⬢ Select the correct auto-configuration modules explicitly
🚀 Building a Spring Boot 4 REST API the Fast Way
A step-by-step walkthrough for quickly creating a CRUD REST API.
⬢ Demonstrate convention-over-configuration in practice
🔍 Extra Reads
Engineering & Careers
✍️ 21 Lessons from 14 Years at Google — Practical reflections on engineering, careers and long-term growth.
🏷 Keep earning your title, or it expires — A reminder that titles only matter if continuously backed by action.
🧪 Your job is to deliver code you have proven to work — A critique of unverified, AI-assisted development practices.
Data & Architecture
🧮 A modern guide to SQL JOINs — A clearer mental model for understanding SQL joins.
🏗 Breaking Silos: Netflix Introduces Upper Metamodel — How Netflix standardizes domain models at scale.
☁️ Microsoft Introduces Postgres-Compatible Azure HorizonDB — A new cloud database built on the Postgres ecosystem.
Tools, IDEs & Productivity
🖥 Why VS Code Still Dominates Frontend Development in 2025 — Why ecosystem momentum keeps VS Code ahead.
🎨 Meet the Islands Theme — The New Default Look for JetBrains IDEs — A calmer, more balanced default UI for daily development.
Originally posted on marconak-matej.medium.com.