It has been a long time, but Jakarta Regexp 1.4 is out with a dozen or so of features and bug fixes.
Most important bug fix probably is support of custom character classes with pre-defined negated classes, like in this example:
[^\D\S]+I wonder how regexp lived so long without such useful construct working...
And, let me know if you happen to use such or similar ([\W\S]+, may be?) expression :-)