Lapack doesn't implement any sparse linear algebra. If you think the landscape of "Java matrix libraries" is fragmented, when really they're all just different takes on wrapping Blas and Lapack or writing equivalent functionality in pure Java, wait until you look into sparse linear algebra libraries. There's no standard API, there are 3ish common and a dozen less common different storage formats, only one or two of these libraries have any public version control or issue tracker whatsoever, licenses are all over the map. The whole field is a software engineering disaster, and yet it's functionality you just can't get anywhere else.
> However there are quite a few sparse blas and lapack implementations now.
There's the NIST sparse blas, and MKL has a similar but not exactly compatible version. These never really took off in adoption (MKL's widely used of course, but I'd wager these particular functions are not). What sparse lapack are you talking about?
> If you want to help us fix it we are hiring ;).
We were at the same dinner a couple weeks ago actually. I'm enjoying where I am using Julia and LLVM, not sure if you could pay me enough to make me want to work on the JVM.