Enthuware

Hey,

The explanation by the second answer sounds wrong. If I understand it correctly, the explanation says basicly the regex is , while it is What indeed would result in the second answer.
If it is the regex how the explanation says, the explanation is at the wrong answer.

The explanation is correct. The first o in the given string is a match because it starts with a word boundary i.e. it matches \\bo

I think the words "... any o immediately follows a word boundary ..." ..should be... " any o that immediately follows a word boundary...".
HTH,
Paul.

I'm confused as to why the word boundary itself is not replaced.
If the string is changed to "?O brother", only the "O" is replaced, and the word boundary itself (the ?) is left there, giving the result "?X brother".
Why does the replaceAll not replace the whole regex pattern result?
Thanks

Because word boundary is considered as zero length. It is not included in the matching value.
-Paul.

Ah ok that makes sense.
Thanks.

Hi,
In your explanation you mention that a word boundary matches also special characthers.. what kind of special characters are you talking about?
Thanks in advance.
The_Nick.

Anything that is not considered a word char i.e. a-zA-Z0-9_. So word boundary will match characters like ;- etc. Please see the JavaDoc for the exact list.

HTH,
Paul.

what do you mean by

(Depending on ?m)

If you specify ?m in your expression, it will match line break otherwise not.
See this for details:
http://www.mkyong.com/regular-expressio ... mple-java/
and
http://stackoverflow.com/questions/3651 ... expression

Where is the word boundary here, before the first o ?

Yes, that is the first word boundary.