Try http://numpy.scipy.org/ (assuming you're fine with an interpreted language -- otherwise, there is a python compiler, but I know very little about it).

Why languages like Java are not widespread? Well, my view on the subject is the following. You have two kinds of people who do numerical mathematics:

• Some need to squeeze every instruction of performance out of their mission-critical software, and naturally they are worried about aliasing, garbage processing, cache misses. Thus they use plain C or even Fortran, and use all the voodoo they know to make it run faster.
• Some don't, as they develop algorithms for testing/research only, or where the sheer computing time is not the bottleneck. They generally use Matlab, since it is much easier to work with, and as long as you avoid (or recode in C) tight for loops has a reasonable performance.