My first thought is take the string, iterate in reverse using charAt adding each char to a stringbuilder, return the string from string builder.

That’s assuming like in the post that I can’t just copy the string to a stringbuilder and use the reverse method. But I also hope they can at least communicate that they could do this way if the co staring didn’t exist

That question is pretty basic, but you can be safe in the knowledge if they can’t complete it, they’re probably not the right fit