Well, there is the... PShape class, of course!
With some work, I think it can be isolated from PApplet, if you can accept the GPL license of Processing.

That said, if you are not afraid of large libraries, the most well known SVG Java library is Batik. It is a very comprehensive implementation of the standard (one of the first), a reference.
There might be another reference implementation by the W3C itself, perhaps in their Amaya browser, made to test the standards they write.
Another implementation is SVGSalamander, although I never really tried it.