Tighten Java install instructions

Author: adityaathalye

README.md

@@ -86,13 +86,11 @@ Just do the following one by one, and you should be fine.
 You need Java installed.
 
 - Run `java -version` in your terminal.
-- If Java is not installed, please [download and install Java from here](https://adoptopenjdk.net/). Any version should do.
+- If Java is not installed, please [download and install Java from here](https://adoptopenjdk.net/).
+- Any version should do, but prefer Java 8 or higher. We have not tested
+  this project with Java 7.
 - Once you are done, `java -version` should show you a Java version.
 
-Notes:
-
-- We have not tested this project with Java 7.
-
 ## VSCode + Calva
 
 We support VSCode + Calva IDE in the classroom for this workshop. We suggest you use this setup, unless of course, you have already configured your favourite editor for Clojure development. We've listed alternate starter kits below (IntelliJ, Vim, Emacs, Atom), _but_ please avoid [bikeshedding](http://catb.org/jargon/html/B/bikeshedding.html) editors. Just complete the workshop first!