IMHO.....no. If you're already a Java programmer or Android dev. the overlap with Java is a huge win.

However I remember watching a talk that I believe Stuart Halloway gave where he tossed out the statement "if you're not using java.util.Queue to help with concurrency you're doing it wrong." My initial reaction was to think that is brilliant and would solve some of my issues with Clojure, but after that came this feeling of annoyance thinking how the hell was I supposed to know that?! Java rears its ugly head more than Clojure programmers are willing to admit. And even then you don't get the full reach of Java, for example try getting JavaFX and Clojure to play nice together, good luck with that.

Faced with deep diving into the Java world to really get proficient at Clojure or looking elsewhere, personally I looked elsewhere and ended up over at Common Lisp.

It depends on what you mean by "worthing" it. To become a better programmer? Definitely worth it to know Clojure, as it does provide a new programming style that has inspired some other ecosystems. To find a job? Probably not. Clojure is not a popular language.

On the other hand, nowadays you probably can get away with not knowing Java when doing Clojure. There are also Clojures that are not on the JVM. For example, if you do Clojurescript, then you probably need to know some Javascript. There are also natively compiled Clojures for shell scripting, e.g. babashka, etc.

Yes, if you're an application developer that has to build the latest feature to come out of a spin-the-wheel product management meeting. E.g., you're tasked with adding arbitrary custom PDF functionality to your web app. For the majority of tasks, there are Clojure libs but if you need it Java has battle-tested libraries to do all of the tedious (/s) things that keep business-people happy. You can't assume the same for smaller languages/ecosystems.

Depends what you're into. I basically only use Clojure and can't remember the last time I had to know anything about Java. Admittedly I mostly use Clojurescript...

But seriously, I wouldn't worry. You'll have to install Java, and then you won't have to think about Java ever again if you don't want to.