java - Regex Match word that include a Dot -

i have question have sentence example:

"halloanna daveca.nn dave anna ca. anna" 

and wanna match single standing "ca." .

my regex :

(?i)\b(ca\.)\b 

but doesn't work , don't know why. ideas ?

//update

i excecute with:

testsource.replaceall() 

and with

pattern.matcher(testsource).replaceall(). 

both doesn´t work.

you should use this:

pattern.compile("(?i)\\b(ca\\.)(?=\\w)").matcher(a).replaceall("some text"); 

which if omit java escapes gives regex: (?i)\b(ca\.)\w.

every \ in normal regex has escaped in java - \\.

also, before word have word boundary (\b), applies part in string have change whitespace alphanumeric character or other way around. in case have dot, not alphanumeric character, can't use \b @ end. can use \w means non-word character following dot. use \w need ignore in capture group (so won't replaced) - (?=.

another issue used ., matches character, want match real dot, have escape - \., in java string becomes \\..