Remove white space before punctuation in Java

I have a string

"This is a big sentence .  !  ?  !  but I have to remove the space ."   

In this sentence I want to remove all the space coming before the punctuation and should become

"This is a big sentence.!?!  but I have to remove the space." 开发者_Go百科  

I am trying to use "\p{Punct}" but not able to replace in string.

You should use positive lookahead:

newStr = str.replaceAll("\\s+(?=\\p{Punct})", "")

ideone.com demo for your particular string

Break down of the expression:

• \s: White space...
• (?=\\p{Punct}) ... which is followed by punctuation.

Try this regex to find all whitespace in front of punctuation: \s+(?=\p{Punct}) (Java String: "\\s+(?=\\p{Punct})")

You can use a group and reference it in the replacing string:

String text = "This is a big sentence . ! ? ! but I have to remove the space .";
String replaced = text.replaceAll("\\s+(\\p{Punct})", "$1")

Here we capture the punctuation in a group with (\\p{Punct}) and replace all the matched string with the group (named $1).

Anyway, my answer is a mere curiosity: I think @aioobe answer is better :)