/* package whatever; // don't place package name! */
 
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 str = "HH12HH";
		Pattern p = Pattern.compile("HH12|HH");
		List<String> res = new ArrayList<>();
    	if (str.matches("(?:HH12|HH)+")) { // If the whole string consists of the defined values
    		Matcher m = p.matcher(str);
	    	while (m.find()) {
	    		res.add(m.group());
	    	}
    	}
    	System.out.println(res);
	}
}

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