If you are starting off with recursion, here is a set of 15 simple and great recursion problems and solutions that you can start with. These are the questions I solved when I started recursion.
PLEASE TRY TO SOLVE THE QUESTIONS BEFORE SEEING THE SOLUTION.
If you wish to code it out, here's the site where I got the questions from https://codingbat.com/java/Recursion-1. If stuck, feel free to check the solutions in my doc.
HAPPY CODING!!!