Beyond Prompting: Context Engineering with LangChain4J

Developer Week 2026 – San Jose 🇺🇸

Feb. 2026

Ricardo Ferreira

Abstract

Reliable LLM outputs require far more than good prompting: developers must handle tool calling, memory, retrieval pipelines, and structured outputs while keeping consistency across many interactions. This session introduces context engineering as a discipline that treats the model’s context window as an architectural resource to design and manage, and shows through live coding how LangChain4J implements it, building an agentic system with tool calling, short- and long-term memory, retrieval-augmented generation with vector search, and type-safe structured outputs, contrasting naive prompting with an engineered approach to demonstrate gains in accuracy, consistency, and token efficiency.

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Open source

I contribute to LangChain4j, an idiomatic open source Java library for building LLM-powered applications on the JVM. Recent work includes adding native vector search embedding stores so developers can build RAG, recommendation engines, and AI memory systems.

I also ported RedisVL to Go, an open source, AI-native client that brings vector search, semantic caching, LLM memory, semantic routing, rerankers, and an MCP server to the Redis ecosystem for Golang developers.

Speaking

I’ve been speaking at conferences since 2008 and doing it full time as part of my work with DevRel since 2018. My talks go deep on the systems I build with: distributed systems and event streaming, AI engineering and vector search, and the data infrastructure that has to hold up when the demo ends and production begins. Some of the events I’ve spoken at include AWS re:Invent, Microsoft Ignite, Google Cloud Next, KubeCon, Oracle OpenWorld, QCon, Strange Loop, Kafka Summit, Pulsar Summit, JavaOne, DevNexus, JFokus, JNation, and All Things Open.

Ricardo Ferreira presenting on the main stage at AI DevWorld — On the main stage at AI DevWorld

You can find my upcoming and past talks on my speaking calendar. Recordings also live on my YouTube channel, and the code I write for talks, demos, and tutorials is on my GitHub.

Get in touch

Want to talk about distributed systems, AI engineering, or having me speak at your event? Connect with me through any of the social links below.

Who I am

I work at the intersection of distributed systems, AI, and data infrastructure, turning complex technology into things developers can understand, adopt, and build with.

Lately, that means hands-on AI engineering: building vector search, semantic caching, agent memory, and RAG into the data layer, and figuring out how to make AI agents secure enough to ship. I contribute to open-source projects like LangChain4j and RedisVL for Golang.

The AI-native work isn’t a pivot. It draws on the same systems-design foundation I’ve built for 20+ years: designing data systems for scale, moving data fast, watching where systems break; now applied to vectors and agents. I have worked on RDBMS and Big Data at Oracle; event streaming with Apache Kafka and Apache Flink at Confluent; observability at Elastic; AI and developer tooling at AWS; and NoSQL and vector stores at Redis. That foundation is exactly what separates AI demos that work on stage from AI systems that survive production.

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