class Main { public static void main(String[] args) { // Class String String s1 = "Hello"; s1 = s1 + "World"; System.out.println(s1); // Class StringBuffer StringBuffer s2= new StringBuffer ("Halo"); s2.append("Dunia"); System.out.println(s2); // Class StringBuilder StringBuilder s3= new StringBuilder ("Halo"); s3.append("Dunia"); System.out.println(s3); } }