There is a decently long list of breaking changes now. Removing JavaEE modules from the JDK, and restricting sun.misc.Unsafe, are the ones people usually run into.
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.