Hackforge Academy

Category: spring_boot

What is RAG and how to use in java

Published on 07 Jun 2026

Explanation

What is RAG (Retrieval-Augmented Generation)? RAG enhances LLM responses by retrieving relevant information from external data sources before generating an answer.

Code:

// User Question -> Retrieve Context -> 
LLM -> Answer

Explanation

Step 1: Load documents and create embeddings. Documents are split into chunks and converted into vector representations.

Code:

String text = Files.
readString(Paths.get("document.txt"));
Embedding embedding = 
embeddingModel.embed(text);

Explanation

Step 2: Store embeddings in a vector database such as Qdrant, ChromaDB, or Milvus for efficient similarity search.

Code:

vectorStore.add(List.of(new Document(text)));

Explanation

Step 3: Retrieve relevant document chunks based on the user's question and build a prompt with the retrieved context.

Code:

List<Document> docs = .
vectorStore.similaritySearch(question);
String prompt = "Context:\n" +
context + "\nQuestion:\n" + question;

Explanation

Step 4: Generate the final answer using an LLM. Common Java stack: Spring Boot + Spring AI + Ollama + Qdrant.

Code:

String answer = chatModel.call(prompt);

๐Ÿš€ Learn Spring Boot with real-world projects

๐Ÿ’ก Build REST APIs step by step

๐Ÿง  Improve backend development skills

๐ŸŽฏ Get career-ready practical training

Join Our Free WhatsApp Community

Direct access to niche-specific mentors and peers on WhatsApp.

๐Ÿ

Python Community

Discuss Django, FastAPI, AI integration, and automation scripts with 15k+ developers.

Join Python Community
โš›๏ธ

React Community

Master Next.js, Framer Motion, and State Management. Share your latest UI components.

Join React Community
โ˜•

Java Community

Deep dives into Spring Boot, Microservices architecture, and high-performance backend ops.

Join Java Community