public class Main {
    public static void main(String[] args) {
        String s = "Hello, ${name}! You are learning ${lang}!";
        Map<String, String> map = new HashMap<>();
        map.put("name", "Bob");
        map.put("lang", "Java");
        System.out.println(template(s, map));
    }
    static String template(String data, Map<String, String> map) {
        for (String key : map.keySet()) {
            data = data.replaceAll("\\$\\{"+key+"}", map.get(key));
        }
        return data;
    }
}