libregexp-java-doc 1.5-3build1 (amd64 binary) in ubuntu xenial

 Regexp is a 100% Pure Java Regular Expression package. Regular expressions
 are pattern descriptions which enable sophisticated matching of strings.
 In addition to being able to match a string against a pattern, you can also
 extract parts of the match. This is especially useful in text parsing!
 .
 This package provides the Javadoc for the regexp API.