I do not doubt that there are domain where the best libraries are in a particular language, and this language might not be C++.
I am just not convince that java is better than C++ with this regard. (as they are more domain where the best C++ is faster than best java one).
But i think that's beside the point, we are comparing language here, so the existing/quality of characteristics of libraries shouldn't be the main focus (beside the stdlib of course).
Now there is more to choosing a tech. stack than just the programming language, and that include the libraries, current knowledge of the team etc. And i would even venture to say that those might be more important than the programming language per say. But i do believe we can still factor those concern out and compare programming languages, keeping in mind it's only part of the story.
What value is there in that exercise? We never use a given programming language outside of a given task/context. Comparing them absent that is navel gazing.
No, you're not, because comparable libraries in C++ to do many activities, such as at-scale stream processing, simply do not exist in C++.