Java – what is a regular expression that removes spaces in parentheses?

I'm writing a program in Java to accept queries If I had a query like this

insert    
into  
abc      values   (    e,b    );

... what regular expressions can I use to convert it to:

insert into abc values(e,b);

... or:

insert:into:abc:values(e,b);

In fact, I want to know how to write regular expressions to remove spaces in parentheses

Solution

Assuming the parentheses are balanced correctly and there are no nested parentheses, the following will remove all spaces within the parentheses (and only there):

String resultString = subjectString.replaceAll("\\s+(?=[^()]*\\))","");

Its transformation

insert    
into  
abc      values   (    e,b    );

become

insert    
into  
abc      values   (e,b);

explain:

\s+      # Match whitespace
(?=      # only if followed by...
 [^()]*  # any number of characters except parentheses
 \)      # and a closing parenthesis
)        # End of lookahead assertion