JAVA EE: How to use matches method of Pattern class | Java Regex | Java Regular Expressions

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RegexDemo.java

import java.util.regex.Pattern;

public class RegexDemo
{
    public static void main(String[] args)
    {
        /*
         * Parameters:
         * 
         * regex - The expression to be compiled
         * 
         * input - The character sequence to be matched
         * 
         * Returns:
         * 
         * whether or not the regular expression matches on the input
         * 
         */
        
        System.out.println(Pattern.matches(".r", "ar"));//true (2nd char is r)  
        System.out.println(Pattern.matches(".r", "ak"));//false (2nd char is not r)  
        System.out.println(Pattern.matches(".r", "arr"));//false (has more than 2 char)  
        System.out.println(Pattern.matches(".r", "arrr"));//false (has more than 2 char)  
        System.out.println(Pattern.matches("..r", "par"));//true (3rd char is r)  
    }

}