So I should write my own cross-platform interface to the system PRNG? Doesn't that strike you as more prone to error than relying on SecureRandom, which at least has the advantage of having many eyes on it.
And urandom is not cross-platform, so if I were going to write a cross-platform library, how would you suggest doing it? By writing an interface to urandom, then an interface to CryptGenRandom (doesn't that require an FFI?), and then manually going through all of the platforms Java can potentially execute on until I can be sure I've covered all my bases?
I'm pretty sure that's going to be more than 5-10 lines of code.