> Java has the largest, oldest and most explicit data set for the LLM to reference

That seems to be a recommendation for coding with LLMs that don't have access to tools to look up APIs, docs and 3rd party source-code, rather than something you'd chose for "Agentic Coding".

Once the tooling can automatically figure out what is right, what language you use matters less, as long as source code ends available somewhere the agent can read it when needed.

Agree much with your 2nd point though, all outputs still require careful review and what better language to use than one you know inside-out?

I have been learning Go, Swift, and Rust with the help of LLM/ Agents.

basically the terser/safer syntax and runtime compilation errors are a great tight feedback loop for the agent to fix stuff by itself.

Why is this? is there just a insanely large codebase of open source projects in Java (the only thing i can think of is the entire Apache suite)? Or is it because the docs are that expressive and detailed for a given OSS library?

Java's API docs are very complete and explicit.

Certain points about the language, as well as certain long-existing open source projects have been discussed ad-nauseum online. This all adds to the body of knowledge.

I always assumed the LLMs had the most python code to reference, as they seem to default to Python most often if you don't specify