Java has decade(s) of cruft and breaking changes which LLMs were trained on. It's hard to compare. Plus Go compilation speed/test running provides quick iteration for LLMs.
How is Java slow in any of these? Plenty of tricks e.g. AppCDS before the tests.
Sorry, couldn’t help myself.
Meanwhile Go already had a language change, while being less than half its age (loop variable capture).
Plain vanilla java code is really backwards compatible, on both a syntax, and on a binary level.
You can often find decades old jars on some random university site, working with JDK 25 with no issue.