This is great! Quick question: would you mind sharing why you went with Java vs something perhaps more performant like all C/C++ or Rust? I'd suspect language familiarity (which is 100% ok).
Java was the starting point. Back in the day Rust wasn't a thing and C++ projects were quite expensive to maintain. What Java does for us is IDE support, instant compilation time and super easy test coverage. For things that does require ultimate performance we do use C/C++ though. These libraries are packaged with Java and transparent to end user.
Makes sense, that's what I also guessed.
You may also want to check out NetData (a hugely popular OSS project) for ideas how to grow.