It’s certainly not unique to Java but it’s especially common there because it’s a default language many people are taught in classes, and the demand from large moribund organizations means there are more people in total with that kind of experience. If you put out an ad for Rust or Scala developers, you’re not getting applications from plodders whose counselor told them they could get a decent indoor job at a bank with a basic understanding of the language.

JavaScript/NodeJS certainly has a similar version of the problem but a couple decades earlier in the process, and not being the choice of enterprise it’s less common to see people who’ve been doing the same thing for a decade.

Again, as in my previous comment, this isn’t a problem with Java the language but rather a sampling problem with the massive community.