Almost agree, but minor nitpick: the tools and infrastructure (at least most of them) exist on other platforms in the same or better quality as well. Especially dependency management is not necessarily a strong side of Java (one global namespace for types etc.).
I am not entirely sure what you mean by that, but in Java, a runtime type is determined as a combination of its name and its class-loader. You can (and do) have two versions of the same class running alongside one another in different modules of your code.
Granted, supporting this stuff is not easy, but hopefully the long awaited module system planned (currently...) for Java 9 is supposed to make this all both powerful and easy.
