Well, if I was to apply to such a job and saw this kind of mistake, I would point it out in the best way I could.
E.g. "I've been developing in XX language since it was released", "The technology has been available for X years and I started using it shortly after it was made public".
Well, im not a native English speaker so I'm probably a bit short on vocabulary to express it here. But stuff like that, shows that you know what you're talking about without telling them in their faces that they don't.
And some of the applicants are presumably thinking something like "I'm as familiar with this as I'd need to be to perform the job. And I'm not going to mouth off to HR about how they don't know how long Java has been in existence. So I might as well apply."