What about something like “Thinking in Java”? No kidding. Right now, everyone tends to jump into the chosen language as soon as possible. A while ago people on forums used to suggest learning essentials with C, Pascal or others and later switching to the preferred language. Scala has a lot to offer what makes it too complicated for the newcomers, especially for the ones with no background. Therefore, I think that it would be easier and better for them to start with Java.
Aside from that, I would like to point out scala-exercises: starting with basics, interactive, no need to install anything. Almost as good as try.redis.io.