String pattern matching problem in Java

Question

In my program when I\'m using

line.replaceAll(\"(\", \"_\");

I got a RuntimeException:

 at java.util.regex.Pattern         


        

Answer 1

The error message above the stack trace is (somewhat) helpful:

Exception in thread "main" java.util.regex.PatternSyntaxException: Unclosed group near index 1 ( ^

(That's what I get in Java 6.) It mentions "regex", "group", and the parenthesis. If you can't see this message, you should check how you're logging/catching/displaying exceptions. It could save you some trouble in the future.