Valhalla is indeed the one effort that could close the biggest gap with native languages. Java Vs C or Rust for networked applications have comparable CPU utilisation with comparable throughput, but memory consumption can be >100x. Project Valhalla is the only thing that could potentially change that. The problem I do see is that even after the language and JVM have value types, the vast extense of libraries that people use are unlikely to change to leverage them. But for projects that control most of their own dependencies, it will be a clear win.

I think over a few years, most of the major dependencies will adopt some of the benefits of Valhalla; at least in the performance sensitive parts.