Java : Phone number validation using regular expression

package com.lnn.regex;

import java.util.regex.Matcher;

import java.util.regex.Pattern;

public class PhoneNumberValidation {

      private static final Pattern PhoneNumberPattern = Pattern.compile("[0-9]{3}[-]{0,1}[0-9]{4}");

      public static boolean isValidPhoneNumber(String phone) {

            Matcher matcher = PhoneNumberPattern.matcher(phone);

            return matcher.matches();

      }

     

      public static void main(String[] args) {

            System.out.println(isValidPhoneNumber("123-4567"));

            System.out.println(isValidPhoneNumber("1234567"));

      }

}