Test.java

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

class Test {
    public static void main(String[] args) {
        String command = "while; incr; decr";
        Pattern commandPattern = Pattern.compile("([while,incr,decr])");
        Matcher matcher = commandPattern.matcher(command);
        if (matcher.find()) {
            System.out.println(String.format("Group: %s", matcher.group(1)));
        }

    }
}