You will need to have a Java Runtime Edition (usually installed on most computers by default) to run any Clojure applications.
Check you have a Java runtime on your system path by typing the following in a terminal window:
Java may also be available via your operating systems package manger, for example on Ubuntu / Debian systems this would be installed via sudo apt-get install openjdk-8-jre`
Hint ClojureScript uses the Google Closure compiler and build tools that require a Java Virtual machine. However, work is in progress to make ClojureScript self hosting. See articles such as ClojureScript Next and Bootstrapped ClojureScript FAQ for pro's and con's of this approach.