I have yet to see a maintainable Java project of any reasonably large size, anywhere.
Java programs are larger than those in other mainstream languages, just by dint of the verbosity of the language (and research backs this up; studies showing errors per LOC are consistent regardless of the language).
There is definitely a certain writing style among Java developers that is overly abstract, but there are plenty of examples of properly written code bases as well.
Also, Java’s “verbosity” is pretty much only a constant factor, and not even necessarily in terms of LOC, but width. What research also show is the benefits of static typing. Also, I am fairly sure there is some survivorship bias working in the background, where an ugly java version of a complex domain survived because the language’s great observability sort of kicking it into a working spaghetti code state, while other projects died a premature death.