Belgian Java User Group

For the first BeJUG of 2026, we're heading back to Kortrijk! Antonio Goncalves will show us how to add intelligent conversational AI in your Java application! This presentation demonstrates how to build a production-ready chatbot from scratch using LangChain4j, progressing from basic chat functionality to a sophisticated AI assistant with memory, content moderation, document retrieval (RAG), and business integration.

This time, you can find us at Sweet Mustard's new offices in Kortrijk (same address and parking, but in a new building with the Cronos logo). Many thanks to them for hosting us! Check them out at: sweetmustard.be

Schedule

• 18:00: Doors + Food and Drinks
• 19:00: Intro and BeJUG updates
• 19:15: Build an AI-Infused Chat Bot with LangChain4j
• 20:45: Mingling

Build an AI-Infused Chat Bot with LangChain4j
Ever wondered how to add intelligent chat capabilities to your Java applications without drowning in AI complexity? This hands-on presentation walks through building an AI-powered customer service chatbot, showcasing LangChain4j's developer-friendly approach to enterprise AI integration.

What You'll Learn:

• Start Simple: WebSocket chat integration with Quarkus
• Add Intelligence: Integrating an LLM for natural conversations
• Make It Safe: Content moderation with a moderation AI-model to handle inappropriate messages
• Remember Context: Persistent chat memory using volatile memory and then Redis for multi-session conversations
• Access Knowledge: RAG (Retrieval Augmented Generation) with Qdrant vector database for company-specific responses
• Connect Business: Function calling to access live inventory, user data, and business logic

Key Technical Highlights:

• Real Implementation: Working e-commerce chatbot with actual business integration
• Progressive Enhancement: Each step builds naturally on the previous functionality
• Production Ready: Includes guardrails, error handling, memory management, and monitoring
• Type-Safe AI: LangChain4j's annotation-driven approach eliminates boilerplate
• Enterprise Features: Content moderation, persistent memory, RAG, and function calling

This presentation is perfect for Java developers looking to add AI capabilities to existing applications, architects designing conversational AI systems, and anyone interested in practical AI integration patterns.

Live demo included: See the complete chatbot in action, from basic echo responses to intelligent customer service with document retrieval and business system integration.

About Antonio
Antonio Goncalves (LinkedIn, GitHub) is a Principal Software Engineer at Microsoft, living in Paris. He evolved in the Jakarta EE landscape for a while (Spring, Micronaut, Quarkus, etc.) and then moved on to AI. From distributed systems to microservices and functions, today he helps his customers develop intelligent applications that run in the Cloud.

Aside from developing, Antonio wrote a few books (LangChain4j, Quarkus and Java EE), talks at international conferences (Devoxx, JavaOne, GeeCon…), writes technical papers and articles, gives on-line courses (PluralSight, Udemy), and co-presents the Technical French podcast Les Cast Codeurs. He has co-created the Paris JUG, Voxxed Microservices, Devoxx France, and Café IA. For all his work for the community he has been made Java Champion a few decades ago.

Additional note: This meetup includes food. We, therefore, ask you to please keep your RSVP status up to date, so we do not waste any of our food.