alt Hacker NewsWell, what frameworks were used? Also what is behind the web requests, what were they doing? Because it's comparing mostly frameworks, not languages.
As for the build tools, unfortunately the scene is not the best on Java - but javac itself is indeed fast.
Yeah javac is pretty great. I was doing Kotlin for some time and I was getting very annoying by how much slower and slower running tests and doing full builds became. I thought it was some issue with the JVM ecosystem. Then I started a project with pure Java and I was blown away by how fast it was. Unit tests in my IDE running as fast as I'm used to in Go. And indeed I was surprised by the speed of the compilation step of the build too. Perhaps Kotlin is doing better now, haven't touched it in a few years, but yeah, Java made some great steps there in the past decades.