How do I compile character classes with quantifier?

This example show you how to attach quantifier to character classes or capturing group in regular expressions.

package org.kodejava.example.util.regex;

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

public class CombineWithQuantifier {
    public static void main(String[] args) {
        //
        // [abc]{3} --> apply quantifier in character class.
        // Find 'a' or 'b' or 'c', three times in a row.
        //
        // (abc){3} --> apply quantifier in capturing group.
        // Find 'abc', three times in a row.
        //
        // abc{3} --> apply quantifier in character class.
        // Find character 'c', three times in a row.
        //
        String[] regexs = {"[abc]{3}", "(abc){3}", "abc{3}"};
        String text = "abcabcabcabcaba";

        for (String regex : regexs) {
            Pattern pattern = Pattern.compile(regex);
            Matcher matcher = pattern.matcher(text);

            //
            // Find every match and print it
            //
            System.out.println("------------------------------");
            System.out.format("Regex:  %s %n", regex);
            while (matcher.find()) {
                System.out.format("Text "%s" found at %d to %d.%n",
                        matcher.group(), matcher.start(),
                        matcher.end());
            }
        }
    }
}

This program will print the following output:

Regex:  [abc]{3} 
Text "abc" found at 0 to 3.
Text "abc" found at 3 to 6.
Text "abc" found at 6 to 9.
Text "abc" found at 9 to 12.
Text "aba" found at 12 to 15.
------------------------------
Regex:  (abc){3} 
Text "abcabcabc" found at 0 to 9.
------------------------------
Regex:  abc{3} 
Wayan Saryada

Wayan Saryada

A programmer, runner, recreational diver, currently living in the island of Bali, Indonesia. Mostly programming in Java, creating web based application with Spring Framework, JPA, etc. If you need help on Java programming you can hire me on Fiverr.
Wayan Saryada

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