I am pretty sure that you can programm java without knowing details about the JVM and I would think, that most java programmers do exactly this. I think only in high performance scenarios knowing more is beneficial?
But I have not touched java in a long time .. as I have indeed choosen the web as plattform.
But I don't feel threatened by the high school kids coming from boot camps.
It's entirely possible that between your skill level and those boot campers is a few(dozen) percents of workforce. But at the same time it's entirely possible that if you are not as quickly progressing as the growth of the industry, you could become a part of the same percentile as bootcampers in no time.
Focus on what you can control and let go of that which you cannot.
A lot of them are senior or principal product engineers at companies you will have heard of.
Whereas with C, its extremely necessary to get into the weeds - otherwise your code just crashes or suffers some memory corruption issue, race condition, etc etc.
yeah that was the whole point of object oriented programming and Java to begin with. You don't need to know the details of the underlying implementation, focus on the problem you're trying to solve.
With less fashionable language that require significant expertise and experience in picking them up like C (understanding the hardware level) and Java (understanding the JVM and OOP concepts) the barriers of entry are much higher and this will mean you have to outrun fewer people in the long run to survive.