- Note about installing java before groovy

Author: Alan Christie

README.md

@@ -8,10 +8,16 @@ text-file format used to both describe and execute built-in tests.
 ## Execution environment
 You will need: -
 
+-   Java
 -   Conda
 -   Groovy (v2.4)
 -   Python
 
+>   It is vital that you install and setup a Java installation (especially by
+    also setting `JAVA_HOME` correctly) _before_ you install groovy. Observed
+    on Windows 7. If you do not groovy assumes a 32-bit environment and
+    then cannot call into a 64-bit java. 
+
 Although the project is based on [Gradle], which is Groovy-based,
 you will need to install **Groovy**. We've tested this framework using Groovy
 `v2.4.11`.