I mentioned a few days ago that writing a quick and dirty regular expression tester would only take a few lines of code. While this is true, once I started adding features it started to grow. I'm posting it here because someone may find it useful.
Runs from command line.
Allows entering regex and text to be searched.
Show matches as well as multiple occurrences with find.
Show matching groups.
Keep track of the most recent regex's and test texts.
Allow editing of current regex and text.
In the code, the RegexTester class is the meat & potatoes. Other classes are there to support the user interface.
The EditDialog was a hack at a modal dialog that allowed for a longer TextField for editing. (I'm sure there must be an easier way.)