I personally find SASS syntax deeply, horribly annoying. For Ruby / Python crowd it may come as second nature; for me as Java guy - not so much. I strongly prefer LESS which builds upon CSS syntax instead of coming up with a new one. That has a nice added advantage of being able to use your existing CSS files "as is" and incorporate LESS features as needed.
That said, neither SASS nor LESS have java ports as far as I know. Both are ruby-based, however, so you can install them under JRuby. The only issue with that approach is JRuby is mind-numbingly slow to start up. It's not a huge deal, though, because you're likely going to use file monitoring in development (and once it does startup it runs very smooth) and you're not going to care as much that your build takes few seconds longer during deployment.
There are also some PHP-based implementations like LessPhp, xCSS and others. Haven't tried them personally, though.
