Java Regex - Boundary Matcher [\b] Match



The Boundary Matcher [\b] matches the word boundary.


The following example shows the usage of boundary matcher.

package com.tutorialspoint;

import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class BoundaryMatcherDemo {
   private static final String REGEX = "\\b";
   private static final String INPUT = "Welcome to TutorialsPoint.COM";

   public static void main(String[] args) {
      // create a pattern
      Pattern  pattern = Pattern.compile(REGEX);
      // get a matcher object
      Matcher matcher = pattern.matcher(INPUT); 

      while(matcher.find()) {
         //Prints the start index of the match.
         System.out.println("Match String start(): "+matcher.start());

Let us compile and run the above program, this will produce the following result −

Match String start(): 0
Match String start(): 7
Match String start(): 8
Match String start(): 10
Match String start(): 11
Match String start(): 25
Match String start(): 26
Match String start(): 29