It's very surprising to hear you say this, as it's so contrary to my experience.
From the smallest programs (Computer Language Benchmarks Game) to pretty big programs (web browsers), from low-level programs (OS kernels) to high-level programs (GUI Applications), from short-lived programs (command-line utilities) to long-lived programs (database servers), it's hard to think of a single segment where even average Java programs will out-perform average C, C++, or Rust programs.
I hadn't heard of QuestDB before, but it sounds like it's written in zero-GC Java using manual memory management. That's pretty unusual for Java, and would require a team of experts to pull off, I'd think. It also sounds like it drops to C++ and Rust for performance-critical tasks.