The Raspberry or Banana Pi have already pre-installed Python.
If you like to stay with Groovy on these nice little devices, here are the instructions to install Groovy.
GVM makes the whole process very easy and convenient.
Open a terminal window and use these commands:
curl -s get.gvmtool.net > installGroovy.sh
chmod u+x installGroovy.sh
gvm install groovy
This will download and install the latest Groovy version.
Check the installed version:
Groovy Version: 2.4.2 JVM: 1.8.0 Vendor: Oracle Corporation OS: Linux
Happy Groovy coding on your Banana Pi,