I must use a commercial Java library, and would like to do it from Python. Jython is robust and I am fine with it being a few dot releases behind. However, I would like to use NumPy as well, which obviously does not work with Jython. Options like CPype and Java numeric libraries are unappealing. The former is essentially dead. The latter are mostly immature and lack the ease of use and wide acceptance of NumPy. My question is: How can one have Jython and Python code interoperate? It would be acceptable for me to call Jython from Cpython or the other way around.
It's ironic, considering that Jython and Numeric (NumPy's ancestor) were initiated by the same developer (Jim Hugunin, who then moved on to also initiate IronPython and now holds some kind of senior architect position at Microsoft, working on all kind of dynamic languages support for .NET and Silverlight), that there's no really good way to use numpy in Jython. The closest thing to that, which I know of, is the "jnumerical" project -- the (scarce) docs are on sourceforge, but the updated sources are on bitbucket.
"Numeric Python", what jnumerical implements, is not as slick and streamlined as its numpy descendant, but it has about the same functionality and shares a lot of the concepts and philosophy, so maybe you could find it usable -- worth checking out, at least.