Regular Expressions 101

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/
^([\w\d._-]+)(\.jar)$
/
mg
^ asserts position at start of a line
1st Capturing Group
([\w\d._-]+)
Match a single character present in the list below
[\w\d._-]
+ matches the previous token between one and unlimited times, as many times as possible, giving back as needed (greedy)
\w matches any word character (equivalent to [a-zA-Z0-9_])
\d matches a digit (equivalent to [0-9])
._-
matches a single character in the list ._- (case sensitive)
2nd Capturing Group
(\.jar)
\. matches the character . with index 4610 (2E16 or 568) literally (case sensitive)
jar
matches the characters jar literally (case sensitive)
$ asserts position at the end of a line
Global pattern flags
m modifier: multi line. Causes ^ and $ to match the begin/end of each line (not only begin/end of string)
g modifier: global. All matches (don't return after first match)
Your regular expression does not match the subject string.Try launching the debugger to find out why.

Regular Expression
No Match

/
/
mg

Test String