Language models become much more useful when they can answer questions about information they were never trained on, including your internal documentation, product manuals, policies, and other proprietary data. Prompting alone cannot solve this, because the model simply does not have access to that knowledge. Retrieval-Augmented Generation, or RAG, is the most common way to bridge that gap.
Spring AI comes with solid support for building RAG systems. It has been almost three years since Spring AI showed up, and in that time it has grown from an experimental member of the Spring portfolio into a mature layer over chat models, embedding models, vector stores, and the plumbing that sits between them, which happen to be exactly the pieces a RAG system needs.