Hi, I am playing with gnu.regexp these days and finding more and more to do before it becomes comparable with Sun's JDK. Although I will continue to make efforts on gnu.regexp, I am beginning to try another thing. I have found oniguruma, the regex library which is used as a regex engine of Ruby, is pretty good. It already supports most part of java.util.regex.Pattern syntax. http://www.geocities.jp/kosako3/oniguruma/ I will write a JNI interface to oniguruma, and make it switchable with gnu.regexp. Users can select one of the supported regexp engines at their choice.