import java.util.*;
import java.lang.*;
import java.io.*;
import java.util.regex.*;
/* Name of the class has to be "Main" only if the class is public. */
class Ideone
{
	public static void main (String[] args) throws java.lang.Exception
	{
		String text = "aaaaaaBccccCCCCd"; //a6B1c4C4d1
        String regex = "(.)(\\1*)";
        String pattern = "test";
        Pattern r = Pattern.compile(regex);
        Matcher m = r.matcher(text);
        StringBuffer sb = new StringBuffer();
        while (m.find()) {
            m.appendReplacement(sb, m.group(1) + (m.group(2).length()+1));
        }
        m.appendTail(sb); // append the rest of the contents
        System.out.println(sb);
	}
}

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