Java in a large way has been eclipsed by most other languages, and developers kind of have a way of making fun of old technologies, like a lot of the same jokes are made about PHP which is still very popular but outdated. In reality Java is also still incredibly popular and knowing it is certainly a benefit. It’s just a collective joke.
Like 2 months ago the only time I heard the word Zionist was in my world religions class, now I guess the entire world is suddenly run by them.