To extract specific information in the stack trace using regular expression
If you wish to include the hat ^ and dollar $ signs, then the regex can be rewritten as:

^.*\s+at widget\.List\.(\w+)\((\w+\.java)\:(\d+)\)$


Ofcourse, you can still use \d{3,4} instead of \d+ but that'll result in you missing the errors in line numbers less than 100(like 1 to 99).

Similarly, you can use \w+ in place of [a-zA-Z]+ or simply, [A-z]+ will work too.