Claro requires a Java Runtime Environment. If you run the installer it will check for the availability of a correct Java Runtime Environment installation. If the check fails, the installer informs you and send you to a download page where you can download it. You need version 7 or higher, and you need a 64bit version.
This is a url where you can download such a Java Runtime Environment:
For Windows you would choose this file: jre-8unn-windows-x64.exe.
On recent Mac OS X versions a correct Java Runtime Environment is usually already installed.