How do I use Java regex to find all repeated character sequences in a string?

Use Java and regex to parse a random string to find repeated sequences

Consider string:

aaabbaaacccbb

I want to find a regular expression that can find all matches in the above string:

aaabbaaacccbb
^^^  ^^^

aaabbaaacccbb
   ^^      ^^

What is a regex expression that will check any repeated character sequence of the string and return the group of these repeated characters so that group 1 = AAA and group 2 = BB Also note that I used a sample string, but any duplicate characters are valid: ronronjoejoe

Solution

Do it in this way.

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

public class Test {
    public static void main(String[] args) {
        String s = "aaabbaaacccbb";
        find(s);
        String s1 = "RonRonRonJoeJoe ....,";
        find(s1);
        System.err.println("---");
        String s2 = "RonBobRonJoe";
        find(s2);
    }

    private static void find(String s) {
        Matcher m = Pattern.compile("(.+)\\1+").matcher(s);
        while (m.find()) {
            System.err.println(m.group());
        }
    }
}

OUTPUT：

aaa
bb
aaa
ccc
bb
RonRonRon
JoeJoe
....,---