public static String concat(Object obj1, Object obj2, Object obj3) { return cat(obj1, obj2).append(obj3).toString();
public static String concat(Object obj1, Object obj2) { return cat(obj1, obj2).toString();
    public static String concat(Object obj1, Object obj2, Object obj3) {        return cat(obj1, obj2).append(obj3).toString();    }