The following code shows how to replace all 10-digit phone numbers by formatted phone numbers.
The String class uses Pattern and Matcher class internally to get the result.
public class Main { public static void main(String[] args) { // Prepare the regular expression String regex = "\\b(\\d{3})(\\d{3})(\\d{4})\\b"; String replacementText = "($1) $2-$3"; String source = "1234567890, 1234567, and 1234567890"; // Use replaceAll() method of the String class String formattedSource = source.replaceAll(regex, replacementText); System.out.println(formattedSource); }/*from w w w .j ava2 s . c o m*/ }