I am using the Pattern and Matcher classes to search text from an email.  Sometimes, I get an exception that says Regex too complicated.  I can't find any information on this.  Does anyone know what can cause?  I get the premise of the exception but don't know what to do to fix it.  If I put my regular expression and sample text into the tester on this site, http://www.fileformat.info/tool/regex.htm.  It works fine and returns what I want.  From what I understand Salesforce uses similar functionality as Java which the above site is using.  Any ideas?  Thanks.