Jfokus 2026
2026-02-02..2026-02-04
Stockholm, Sweden
Jfokus ·
[Jfokus 2016, Jfokus 2018, Jfokus 2019, Jfokus 2021, Jfokus 2022, Jfokus 2023, Jfokus 2025, Jfokus 2026]
| title | author | length |
|---|---|---|
| High Speed Java Development with LLMs and Agents Fast, Clean, Maintainable | Adam Bien | 53m |
Claims that LLM agents generate production‑ready Java fast and clean are demonstrated concretely: Quarkus + MicroProfile starter projects are cloned in VS… | ||
| Ask the Java Architects | Brian Goetz, Per Minborg, Viktor Klang | 53m |
Answers focus on concrete tradeoffs and designs not slogans For reconstruction the claim is that deconstructibility on classes can let wither style… | ||
| Spec-driven Development using Coding Agents | Arun Gupta | 50m |
Builds a 3x3 tic‑tac‑toe app from a 4,500‑line natural‑language spec, using a multi‑agent pipeline (scout → strategist → executor), Python + FastAPI + Pydantic… | ||
| Bootiful Spring Boot 4 | Josh Long | 52m |
Spring Boot 4 demo builds an adoption service using Maven, Java 25 (showing Java scripting), Spring Modulith with an event_publication outbox table for… | ||
| The Best Simple System for Now | Daniel Terhorst-North | 56m |
Argues for the Best Simple System for Now: build the smallest thing that meets today's needs, resist speculative generality, delete unused code and trust… | ||
| Modern Java Puzzlers | Simon Ritter | 50m |
Shows concrete failures and surprises: switch expressions require exhaustiveness while legacy switch statements do not, but using enhanced switch or case null… | ||
| The Psychology of Code | Victor Rentea | 51m |
Survey finds 80% admit imposter syndrome; common failures are sunk‑cost attachment to prototypes and endless bike‑shedding over brackets, imports and naming… | ||
| Concurrency in Spring Boot Applications: Making the Right Choice | Andrei Shakirin | 58m |
In the dynamic landscape of Spring Boot applications, selecting the right concurrency model is critical — but which approach best fits your business case? This… | ||
| Machines, Learning, and Machine Learning | Dylan Beattie | 50m |
A mix of concrete failures and experiments: a smart blood‑pressure cuff reports health scores 5→10 because it reads calendar dates; a haunted test traces to a… | ||
| Intelligent JVM Monitoring: Combining JDK Flight Recorder with AI | Yagmur Eren | 49m |
A Java agent starts JDK Flight Recorder with a custom JFC and streams ~90 default events (pruned to a custom set) to a central service, which stores events in… | ||
| More Action, More Overview – From 4k to 1M Threads | Merlin Bögershausen | 47m |
Claims that Java 21 virtual threads let a process spawn ~1,000,000 threads (1KB each vs 1MB for platform threads), creating them in microseconds and running… | ||
| When ORM Becomes OMG: Performance Pitfalls in JPA and Friends | Jos Roseboom | 51m |
A demo funfact store uses Java 25, Spring Boot 4, Spring Data JPA, Hikari and Postgress with Testcontainers and a unit test that measures real effects… | ||
| Make Your Code Parallel with the Structured Concurrency API | José Paumard | 48m |
Structured Concurrency arrives as a preview API (structured task scopes in JDK26 preview) that pairs StructuredTaskScope with virtual threads and scope values… | ||
| Full-stack web apps, 100% Java | Marcus Hellberg | 50m |
Build a full-stack web app using only Java: Spring Boot + Vaadin Flow for UI, JPA with an in-memory database for persistence, and Spring AI (OpenAI) for LLM… | ||
| Virtual Threads, Structured Concurrency and Scoped Values: Putting it all together | Balkrishna Rawool | 42m |
Builds a Spring Boot web app (uses Spring Boot 3.5 on JDK 25), flips a flag to enable virtual threads so each request runs on a virtual thread, and replaces… | ||
| Hack Your Brain: Smarter Learning for Devs | Simone de Gijt | 50m |
Claims that learning restructures neuronal connections and that sense and meaning predict whether new material survives the 18–24 hour forgetting window… | ||
| Agentic AI Patterns | Mario Fusco, Kevin Dubois | 51m |
Presentation claims a concrete library for Java (LangChain for Java + Quarkus) that implements four orchestration patterns — sequence loop parallel conditional… | ||
| Never Trust a Monkey: The Chasm, the Craft, and the Chain of AI-Assisted Code | Baruch Sadogursky | 51m |
Claims a concrete pipeline to make AI code trustworthy: Intent Integrity Chain that runs prompt → spec → test → code, with specs human-reviewed, tests… | ||
| Level Up Your Java Streams with Gatherers | Hinse ter Schuur | 44m |
Java 24/25 adds Stream Gatherers as a generic way to write custom intermediate stream operations, with five built-ins used here: window fixed (group 60-minute… | ||
| What's your favourite number of threads? | Ryan Healey | 13m |
Claim: the right thread count really depends — CPU-bound tasks hit a plateau around 8–12 threads on an 8-core box, while IO-bound work follows the formula… | ||
| The Renaissance Developer: Building Better, Safer, & Quicker with AI-Powered Spec-Driven Development | Kevin Azijn | 47m |
Demonstrates using the Kiro agentic IDE to add authentication to the Spring Pet Clinic with Amazon Cognito, generating steering docs, a spec, technical design… | ||
| Secrets of Agentic Memory Management | Brian Sam-Bodden | 51m |
Prototype Java Spring memory server implements six memory types (semantic, episodic, procedural, entity and variants), a memory type registry and modules, and… | ||
| Java Performance Update: From JDK 21 to JDK 25 | Per Minborg | 51m |
JDK 25 vs 21 lists 13 concrete wins: energy drops ~24% on a Spring Boot workload, JIT and GC changes lift SPECjbb scores ~10% without recompilation, and a new… | ||
| JDK 25's new CPU-Time Profiler | Johannes Bechberger | 45m |
JDK 25 adds a CPU-time profiler that samples by CPU consumption rather than wall clock, producing one sample per 10ms of CPU time (bounded by a default 500… | ||
| How to Write Bad Java Code | Pratik Patel | 15m |
Shows concrete fixes: replace repeated string concatenation that creates ~7 temporaries and O(n^2) behavior with a string builder, prefer… | ||
| DIY Technical Marketing - Real World Tips For Building A Successful Developer Brand | Dominika Tasarz | 20m |
Personal branding yields measurable returns: a Hinge study shows visible experts can command up to 14× higher fees, Brand Builders finds 74% more trust and 63%… | ||
| The Java Class File API | Cay Horstmann | 51m |
Many third party libraries like ASM BCEL and Javassist exist but Java 24 now provides a standard Class File API since Java 24 that parses and builds class… | ||
| Strangling the dragon: modernizing legacy systems with the Strangler Fig pattern | Daniel Raniz Raneland | 46m |
Describes using the Strangler Fig pattern to replace a legacy image service by incrementally moving functionality into a new job service, a small JavaScript… | ||
| Beyond Senior Dev: The next steps for the technical career | Bruno Souza | 17m |
Five concrete career tracks beyond senior: people (management, meetings become the work, power to hire/fire); tech (staff/principal/distinguished — staff… | ||
| Herding LLMs: Predictable Outcomes from Unpredictable Agents | Renato Guerra Cavalcanti | 56m |
Claims that event-sourced, durable workflows plus domain engineering and code-level guardrails turn chaotic LLM agents into reliable services, demonstrated by… | ||
| Beyond local tools: Dive into the Model Context Protocol (MCP) | James Ward | 50m |
MCP is shown as a JSON RPC protocol that standardizes tool, resource and prompt integration so an agent calls a single API instead of many REST/GraphQL… | ||
| Agents, Tools, and MCP, oh my! Next-level AI concepts for developers | Jennifer Reif | 45m |
Spring Boot app uses OpenAI for reasoning, Neoforj as the Neoforj vector store, and five hard‑coded tools (three repository queries + RAG + graph RAG) so an… | ||
| How to build your own fun and absurd pair programmer | Alexander Chatzizacharias | 52m |
A cheeky local pair-programmer called Pip the pair programmer is built as an IntelliJ plugin talking to a Spring Boot Kotlin backend, using Quarkus components… | ||
| Tame your Llama, run AI in Java | Lutske de Leeuw | 49m |
Java runs local LLMs with practical, runnable code using Olama4j + Olama server and LangChain4j, creating custom models like a “llama animal expert” and a… | ||
| Unbreakable by Design: The Secret Tech of Antifragile Software | Iryna Dohndorf | 48m |
Explains how antifragile software actually works: a write‑ahead log with Kafka‑backed durable queues, Redis cache and per‑service shards removes single points… | ||
| Three flavors of generational GC: G1, ZGC, Shenandoah | Oleksandr Kachur | 15m |
All three collectors adopt a generational design in generational ZGC in Java 25 and behavior differs sharply: Capo benchmarks show ZGC has the lowest pause… | ||
| GraalVM + Wasm: Fast, Efficient, Portable Apps | Fabio Niephaus | 49m |
GraalVM compiles JVM apps into Wasm with the new GraalVM Web Image preview and embeds Wasm modules in JVM apps via the GraalWasm runtime. Demo compiles a Rust… | ||
| Systems playing nicely: Building resilient integrations in an unpredictable world | L. Peter Deutsch | 49m |
Parkster runs several hundred thousand parkings a day and uses a transactional outbox plus workers and message queues to guarantee eventual consistency; a… | ||
| Brokk: an AI-Native Code Platform | Jonathan Ellis | 47m |
Brokk is a Java standalone app that supervises AI coding agents using static analysis and dependency decompilation so models see parsed APIs and decompiled… | ||
| Java: To infinity and beyond | Sharat Chander | 55m |
Java ships Java 25 and is already on early access for Java 26 with GA slated for March 17; the project moves to a six‑month release cadence to reduce latency… | ||
| Build your own @MiniService | Jennifer Wadin | 11m |
Builds a tiny @MiniService annotation and an Inject field annotation, then uses reflection to scan, instantiate, inject, store a handful of classes listed by… | ||
| CUPID For Joyful Coding | Daniel Terhorst-North | 49m |
Proposes a concrete five-letter rubric—CUPID = Composable, Unix philosophy, Predictable, Idiomatic, Domain-based—as a practical lens to assess and improve real… | ||
| Java Meets AI: Empowering Spring Developers to Build Intelligent Apps | Timo Salm, Sandra Ahlgrimm | 44m |
Claims enterprise Java is ready for generative AI and shows concrete code: a working recipe finder demo that uses GPT‑4o for text, Dolly 3 for images, Spring… | ||
| Dehumanizing Agents: Why Explainability is Crucial in the LLM Era | Lucía Conde-Moreno | 50m |
Argues that explainability is nonnegotiable for LLMs and shows concrete tools: LIME proves fragile on text and scales poorly, so an internal AutoML called auto… | ||
| The Browser is a Marvelous Thing | Andreas Wänqvist | 50m |
Live demos show about 50 concepts in 45 minutes including CSS anchoring that positions tooltips with zero JavaScript, scroll‑driven animations replacing dozens… | ||
| Opening On Fire with FAE Production | 06m | |
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| Supercharge your JVM performance with Project Leyden | Ana-Maria Mihalceanu | 51m |
Project Leyden with JDK25 shortens startup and time‑to‑peak by supplying an AOT cache created from a training run; JDK24 introduced a three‑phase workflow and… | ||
| Behavioral Software Engineering | Mario Fusco | 44m |
Covers how documented cognitive biases map to everyday engineering choices and gives actionable countermeasures: patternicity (benchmarks showing a spurious 3%… | ||
| Connecting the Dots with Context Graphs | Stephen Chin | 49m |
Shows a working context graphs pipeline built on Neo4j and Aura that loads a BOM and a CycloneDX VEX, extracts entities with the Neo4j LM graph builder, and… | ||
| The Reputation Formula: Turbocharge Your Developer Career | Bruno Souza | 01h 15m |
Reputation is what people believe about you. And it is your reputation that defines the projects you work at, the opportunities you have, the technologies you… | ||
| Healthy Geeks, Better Code: Lessons from Fitness and AI | Markus Eisele | 45m |
Claims that small daily habits improve cognition and code quality, backed by concrete routines: 30‑minute walk starting mornings, breathing sets with longer… | ||
| From Monoliths to Modern Integration Platforms | Pär Turborn | 44m |
Argues that modern integration platforms must balance developer autonomy with security by design and provide versatile tools like Kafka and Camel-style EIP… | ||
| Dockerize Securely: SBOMs + Attestations + Bake | Mohammad-Ali A'râbi | 37m |
Explains how to generate SBOMs during docker build (buildkit flag) so multi-stage dependencies get included, how Docker Scout auto-uses attached SBOMs to find… | ||
| Writing GPU-Ready AI Models in Pure Java with Babylon | Lize Raes | 49m |
Demonstrates three concrete paths: load an existing ONNX model via ONNX+Panama bindings and run it on local runtimes (CoreML on a Mac with unified memory) —… | ||
| The developer's guide to making money in the open-source galaxy | Ronald Dehuysser | 53m |
An open-source Java library called JobRunner becomes a paid business: a database-backed distributed background job system with an embedded dashboard, Java 8+… | ||
| Help, I'm an Architect for an Open Source Project! | Andrea Berglund | 14m |
Takes over a design system run as open source and finds a tangled monorepo with a shared core with build-time theming plus duplicated org-specific components… | ||
| AI First Learning | Stephen Chin, Cassandra Chin | 42m |
A concrete AI‑First system maps learning into repeatable workflows for planning, practicing, verifying and retaining skills, with guardrails for correctness… | ||
| Why we skipped SRE and switched to Platform Engineering? | Gang Luo | 48m |
Electrolux replaces hiring more SREs with an internal developer platform that turns Terraform modules into self‑service catalogs using Backstage + Terraform +… | ||
| CI Pulled It, Prod Ran It: The Real Risk in Dependency, by GraphsIlkka Turunen | Ilkka Turunen | 55m |
Data from Sonatype-backed Maven Central shows extreme scale and risk: registries serve 9.8 trillion requests in 2025, Maven Central adds ~3 million gavs, and… | ||
| From Theory to Practice: Real-World Lessons in Post-Quantum Cryptography Migration | Akihiro Nishikawa | 46m |
Quantum risk is closer than many expect: published estimates drop required logical qubits for breaking RSA‑2048 from ~20 million to under 1 million and surveys… | ||
| These Songs Would Make Some Great Code Comments | Hanno Embregts | 16m |
Argues that popular songs map to concrete software tasks and shows exact examples across the lifecycle: requirement-gathering, implementation patterns, commit… | ||
| Introduction to Verifiable Credentials | Sergey Beryozkin | 47m |
Covers verifiable credential basics and concrete formats: SD‑JWT for selective disclosures, embedded proofs, and BBS+ suites enabling unlinkable proofs; uses… | ||
| Ka-Ching! How Enterprises Measure LLM Performance and Cost | Cedric Clyburn | 50m |
A working POS demo logs ~50 real prompts (33 KB) and feeds them into an SLO-driven benchmark pipeline that uses Guide LLM against a local VLM inference server… | ||
| Supply Chain Security, why should I care? | Magnus Eklund | 14m |
Supply chain attacks rise ~700% recently and six of seven project vulnerabilities come from dependencies, with 13% of downloads still on the log4j vulnerable… | ||
| Beyond Code Generation: Governing AI Agents Across the DevSecOps Lifecycle | Mattias Soderberg | 51m |
Argues that governing AI agents across planning, coding, security and CI/CD avoids shifting the bottleneck downstream and can turn weeks of triage into… | ||
| Apache Spark Lakehouse Pushdowns with Transpilation | Holden Karau | 47m |
Claim: adding type information often makes Spark 10–400% slower because typed UDFs force full-row reads, so the project transpiles Python/Scala/JVM UDFs into… | ||
| Case study BYLES: How Java, standards, and community helped education equality | Richard Fichtner | 50m |
A university team turns a paper screening into a Kubernetes-hosted web platform that hits peaks of 5,000 parallel users and screens 233,000 kids across ~13,000… | ||
| Unbundling of the Cloud Data Warehouse: Open Source Databases and Data Lakes | Zoe Steinkamp | 40m |
Argues that open data lake formats plus fast analytical DBs replace monolithic cloud warehouses by example: Apache Iceberg / Delta Lake / Hudi as catalogs… | ||
| Shift Left on Accessibility: Beyond the Audit | Ramona Domen | 50m |
European law now requires accessible new releases and forces legacy fixes by 2030, so accessibility becomes continuous rather than a one‑off audit. Practical… | ||
| Green AI with JobRunr: Sustainable training and inference on the JVM | Ronald Dehuysser | 17m |
Small Spring Boot app collects session feedback, summarizes it with a local LLM (GPT OSS 20B via LangChain for Java), saves a Markdown summary, and uses… | ||
| From Specs to Decks: A Tale of Bugs, DJs & the Importance of Hobbies | Lucía Conde-Moreno | 16m |
A software engineer describes concrete, repeatable lessons from DJing: five‑minute breaks boost creativity and a one‑minute stand raises blood flow ~15%… | ||
| Please pass the salt: Serve up passwords with a side of entropy | Brad Wood | 43m |
Passwords must be hashed not encrypted, using bcrypt/argon2/scrypt with per-user salts and a tunable work factor so each hash takes about a half-second work… | ||
| Run to the light Carol Anne: Auditing with Lighthouse | Chris DeMars | 14m |
Lighthouse audits site performance, accessibility, best practices, SEO and limited security; Chrome DevTools flame charts supplement Lighthouse and pair… | ||
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