❯ Guillaume Laforge

Java

Javelit to create quick interactive app frontends in Java

Have you ever heard of Javelit? It’s like Streamlit in the Python ecosystem, but for the Java developer! I was lucky that the project creator reached out and introduced me to this cool little tool!

Javelit is a tool to quickly build interactive app frontends in Java, particularly for data apps, but it’s not limited to them. It helps you quickly develop rapid prototypes, with a live-reload loop, so that you can quickly experiment and update the app instantly.

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Building AI Agents with ADK for Java

At Devoxx Belgium, I recently had the chance to present this new talk dedicated to ADK for Java, the open source Agent Development Kit framework developed by Google.

The presentation covered:

  • an introduction to the notion of AI agents
  • how to get started in a Java and Maven project
  • how to create your first agent
  • how to debug an agent via the Dev UI
  • the coverage of the various tools (custom function tools, built-in tools like Google Search or code execution, an agent as tool, MCP tools)
  • an overview of the different ways to combine agents into a multi-agent system: sub-agents, sequential agents, parallel agents, loop agents
  • some details on the event loop and services (session and state management, artifacts, runner…)
  • structured input / output schemas
  • the various callbacks in the agent lifecycle
  • the integration with LangChain4j (to give access to the plethora of LLMs supported by LangChain4j)
  • the definition of agents via configuration in YAML
  • the new long-term memory support
  • the plugin system
  • the new external code executors (via Docker containers or backed by Google Cloud Vertex AI)
  • how to launch an agent with the Dev UI from JBang

Slides of the presentation

The slide deck of this session is embedded below:

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Creative Java AI agents with ADK and Nano Banana 🍌

Large Language Models (LLMs) are all becoming “multimodal”. They can process text, but also other “modalities” in input, like pictures, videos, or audio files. But models that output more than just text are less common…

Recently, I wrote about my experiments with Nano Banana 🍌 (in Java), a Gemini chat model flavor that can create and edit images. This is pretty handy in particular for interactive creative tasks, like for example a marketing assistant that would help you design a new product, by describing it, by futher tweaking its look, by exposing it in different settings for marketing ads, etc.

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Creating a Streamable HTTP MCP server with Micronaut

In previous articles, I explored how to create an MCP server with Micronaut by vibe-coding one, following the Model Context Protocol specification (which was a great way to better understand the underpinnings) and how to create an MCP server with Quarkus.

Micronaut lacked a dedicated module for creating MCP servers, but fortunately, recently Micronaut added official support for MCP, so I was eager to try it out!

For the impatient

You can checkout the code we’ll be covering in this article on GitHub.

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Generating videos in Java with Veo 3

Yesterday, we went bananas 🍌 creating and editing images with Nano Banana, in Java. Now, what about generating videos as well, still in Java, with Veo 3?

Especially since this week, Google announced that Veo 3 became generally available, with reduced pricing, a new 9:16 aspect ratio (nice for those vertical viral videos) and even with resolution up to 1080p!

In today’s article, we’ll see how to create videos, in Java, with the GenAI Java SDK. We’ll create videos either:

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Generating and editing images with Nano Banana in Java

By now, you’ve all probably seen the incredible images generated by the Nano Banana model (also known as Gemini 2.5 Flash Image preview)? If you haven’t, I encourage you to play with it within Google AI Studio, and from the Gemini app. or have a look at the @NanoBanana X/Twitter account which shares some of its greatest creations.

As a Java developer, you may be wondering how you can integrate Nano Banana in your own LLM-powered apps. This is what this article is about! I’ll show you how you can use this model to:

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Mastering agentic workflows with ADK: the recap

Over the past few articles, we’ve taken a deep dive into the powerful agentic workflow orchestration capabilities of the Agent Development Kit (ADK) for Java. We’ve seen how to build robust, specialized AI agents by moving beyond single, monolithic agents. We’ve explored how to structure our agents for:

In this final post, let’s bring it all together. We’ll summarize each pattern, clarify when to use one over the other, and show how their true power is unlocked when you start combining them.

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Mastering agentic workflows with ADK: Loop agents

Welcome to the final installment of our series on mastering agentic workflows with the ADK for Java. We’ve covered a lot of ground:

Now, we’ll explore a pattern that enables agents to mimic a fundamental human problem-solving technique: iteration. For tasks that require refinement, trial-and-error, and self-correction, the ADK provides a LoopAgent.

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Mastering agentic workflows with ADK for Java: Parallel agents

Let’s continue our exploration of ADK for Java (Agent Development Kit for building AI agents). In this series, we’ve explored two fundamental agentic workflows:

But what if your problem isn’t about flexibility or a fixed sequence? What if it’s about efficiency? Some tasks don’t depend on each other and can be done at the same time. Why wait for one to finish before starting the next?

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Mastering agentic workflows with ADK for Java: Sequential agents

In the first part of this series, we explored the “divide and conquer” strategy using sub-agents to create a flexible, modular team of AI specialists. This is perfect for situations where the user is in the driver’s seat, directing the flow of conversation. But what about when the process itself needs to be in charge?

Some tasks are inherently linear. You have to do Step A before Step B, and Step B before Step C. Think about a CI/CD pipeline: you build, then you test, then you deploy. You can’t do it out of order… or if you do, be prepared for havoc!

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