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 first argument to string.replaceAll is a regular expression, not just a string. The opening left bracket is a special character in a regex, so you must escape it:

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

Alternatively, since you are replacing a single character, you could use string.replace like so:

line.replace('(', '_');