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Reposted by Johannes Rabauer

Quarkus @quarkus.io · 1d

Securing LLM Responses in Java: Guardrails with Quarkus and LangChain4j
Learn how to protect your AI applications from prompt injection, unsafe outputs, and risky prompts with practical guardrail patterns in Quarkus.

www.the-main-thread.com/p/java-quark...

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Johannes Rabauer @rabauer.bsky.social · 3d

It looks like you changed passwords since the leak: I tried to login to localhost:8080 with password "pw", but access was denied 😂

Good for you! :)

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Johannes Rabauer @rabauer.bsky.social · 5d

🧠 Open-source & still evolving:
github.com/JohannesRaba...

What would you add next, smarter summaries, multi-agent explorers, or something wild?
#LangChain4j #Quarkus #Ollama #pgvector #ApacheTika #AI #Java #LLaMA3

GitHub - JohannesRabauer/quanta: ai-file-search - lets you find files in a natural language way and summarizes files

ai-file-search - lets you find files in a natural language way and summarizes files - JohannesRabauer/quanta

github.com

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Johannes Rabauer @rabauer.bsky.social · 5d

Quanta tracks file changes, re-vectorizes updates, and returns instant, intelligent answers; all locally.
We debugged Quarkus quirks, Tika headaches, and got Ollama humming 💪
youtube.com/live/OenMqG5...

youtube.com

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Johannes Rabauer @rabauer.bsky.social · 5d

Under the hood:
⚡ Next.js (frontend)
☕ Quarkus + LangChain4j (backend brains)
🦙 Ollama (LLaMA 3.2 embeddings)
🐘 PostgreSQL + pgvector
📄 Apache Tika for text extraction from any file type

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Johannes Rabauer @rabauer.bsky.social · 5d

Just went live building Quanta: an AI-powered file searcher that understands your files 🤖📂
It watches your filesystem, vectorizes docs, and lets you query them in natural language.
Let’s make local AI search actually useful 👇

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Johannes Rabauer @rabauer.bsky.social · 6d

Favorite input field 😅

Johannes Rabauer @rabauer.bsky.social · 8d

Unfortunately because of an emergency in the family i have to postpone the session again...i am really sorry.

Johannes Rabauer @rabauer.bsky.social · 11d

Thank you very much! :)

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Johannes Rabauer @rabauer.bsky.social · 11d

Happy birthday Catherine! :)

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Johannes Rabauer @rabauer.bsky.social · 12d

Thanks! I am unsure about PostgreSQL with pgvector, but since i have the most experience with it, i'm willing to try ^^
Why did you choose PostgreSQL, if you did?

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Johannes Rabauer @rabauer.bsky.social · 14d

I’ll be building Quanta live on stream. 🎥
Join, ask questions, and help me shape it as we go.

Follow along — this will be fun. 🚀
www.youtube.com/live/OenMqG5...

#AI #LangChain4j #Quarkus #Nextjs #Ollama #pgvector #LocalAI #LiveCoding

Building Quanta – An AI File Searcher with Next.js, Quarkus, Ollama & PostgreSQL (Live Coding)

In this live coding session, we’re starting Quanta – an AI-powered file searcher that can watch your filesystem, vectorize documents, and let you search & su...

www.youtube.com

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Johannes Rabauer @rabauer.bsky.social · 14d

To make this work, I’m combining:
⚡ @nextjs.org frontend
⚡ @quarkus.io + @langchain4j.dev backend
⚡ Ollama (LLaMA 3.2) for AI
⚡ PostgreSQL + pgvector for embeddings

A lot of moving parts → one AI-powered file explorer.

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Johannes Rabauer @rabauer.bsky.social · 14d

Quanta will:
📂 Scan your filesystem
🗂️ Catalogue files automatically
📝 Summarize their contents
🔍 Let you find them later with natural language search

No more “where did I save that doc?” moments.

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Johannes Rabauer @rabauer.bsky.social · 14d

After building an AI storytelling app for fun…
…it’s time to create something actually useful. 🚀

Meet Quanta – an AI file searcher.

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Reposted by Johannes Rabauer

Oracle ACE Program @oracleace.bsky.social · 20d

Excited to welcome Johannes Rabauer as our newest Oracle ACE Associate! 🚀
Johannes crafts secure, scalable Java solutions. Cloud, AI, frameworks & clean code—he’s passionate about making developers’ lives easier.
Learn more: ace.oracle.com/ords/ace/pro...
#OracleACE

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Johannes Rabauer @rabauer.bsky.social · 20d

Just unlocked a new achievement: 🏆 Oracle ACE Associate!
Big thanks to the Oracle community 🙌
Catch me dropping Java wisdom at JCON or on YouTube 😂
#OracleACE #Java #DevCommunity @oracleace.bsky.social

A smiling man wearing glasses, a black t-shirt, and a lanyard points to an Oracle ACE Associate certificate. The certificate is awarded to Johannes Rabauer in recognition of technical and community leadership contributions to Oracle communities from July 2024 to August 2025. It is signed by Gerald Venzl, VP of Database Product Management, ACE Program, and dated September 2025. In the background, there is an illustration of a golden trophy with a spade symbol.

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Johannes Rabauer @rabauer.bsky.social · 24d

Part 10: Agents came alive in LangChain4J + Ollama 💡
Part 11 (Sat 20:00 CET): Can we give the entire system memory that persists in PostgreSQL?
One landscape, many agents, real continuity.
Join the experiment 👉 youtube.com/live/Jpid86_...
#Java #AIAgents

Can We Give Our AI Agents Real Memory? (LangChain4J + Ollama + Java Live Coding)

Part 11 – Giving Agents Real Memory in LangChain4J (Live Java Coding with Ollama)In this live session, we’ll tackle one of the hardest (and most exciting) ch...

youtube.com

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Johannes Rabauer @rabauer.bsky.social · 28d

Oh, and if you like, join the live stream today: youtube.com/live/O99hkBr...

Ditching Google ADK: Building Real AI Agents with LangChain4J (Live Java Coding)

YouTube video by Johannes Rabauer

youtube.com

Johannes Rabauer @rabauer.bsky.social · 29d

Highlights with timestamps:
00:52 Fixing persistence
12:41 Fighting LLaMA 3.2:1B
29:00 Google ADK adventures
49:50 Agent prompts
01:13:00 An actual response (finally 🎉)

Full replay 👇
youtube.com/live/xppcyTU...

youtube.com

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Johannes Rabauer @rabauer.bsky.social · 29d

Next session = me going all-in on LangChain4J native agents (no extra SDKs this time).

If you’re a Java dev curious about AI storytelling, Ollama, LangChain4J, or just enjoy watching someone debug themselves into a corner:
👉 Watch the chaos, link below

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Johannes Rabauer @rabauer.bsky.social · 29d

So yeah, Google ADK looked like a shiny enterprise hammer 🛠️…
…but LangChain4J already had the screwdriver I actually needed. 🔧

Lesson learned.

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Johannes Rabauer @rabauer.bsky.social · 29d

The kicker?
LangChain4J already has agents built-in. And they do exactly what I was trying to hack together with ADK — just cleaner, simpler, less… cursed.

Docs: docs.langchain4j.dev/tutorials/ag...

Agents and Agentic AI | LangChain4j

This section describes how to build agentic AI applications using the langchain4j-agentic module. Please note that the whole module has to be considered experimental and is subject to change in…

docs.langchain4j.dev

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Johannes Rabauer @rabauer.bsky.social · 29d

It did *kind of* work… but super strangely.
Like, “AI gremlin whispering from the shadows” strangely.

After more head scratching than I’d like to admit, I realized:
👉 I didn’t need ADK at all.

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Johannes Rabauer @rabauer.bsky.social · 29d

Then came my *brilliant* idea: “Let’s integrate Google’s ADK with LangChain4J. It looks so professional. Surely this is the way.”

Spoiler: it was not the way. 😅
🔗 google.github.io/adk-docs/

Agent Development Kit

Build powerful multi-agent systems with Agent Development Kit

google.github.io

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