How to match a format in string using regular expression?

Below example shows how to match a string pattern with a regular expression. String.matches() method helps to match the string with a regex. Below example checkes weather given string starts with "www" or not.

package com.myjava.string;

public class MyStrMatches {

    public static void main(String a[]){
    
        String[] str = {"www.java2novice.com", "http://java2novice.com"};
        for(int i=0;i < str.length;i++){
            if(str[i].matches("^www\\.(.+)")){
                System.out.println(str[i]+" Starts with 'www'");
            } else {
                System.out.println(str[i]+" is not starts with 'www'");
            }
        }
    }
}