[ajainy]

of course as others pointed out, writing direct exp might be optimal or every dev should learn about it.

BUT in my whole career span, whenever I have to use regex, I spend couple of hrs learning and testing. This kind of library for Java open doors for many other things. (testibility, default library using default methods etc.., integration with streaming ). And as community adds to it, it can be optimized internally. All end user needs to do upgrade versions. Can be extended part of javax validation specs.

[murkle]

Another key point: makes the code readable!