Since Grails 3 Gradle is used as the build tool. The Grails shell and commands use Gradle to execute tasks. When we create a new Grails 3 application a Gradle wrapper is added to our project. The Gradle wrapper is used to download and use a specific Gradle version for a project. This version is also used by the Grails shell and commands. The default version (for Grails 3.0.12) is Gradle 2.3, which is also part of the Grails distribution. At the time of writing this blog post the latest Gradle version is 2.10. Sometimes we use Gradle plugins in our project that need a higher Gradle version, or we just want to use the latest version because of improvements in Gradle. We can change the Gradle version that needs to be used by Grails in different ways.
Grails will first look for an environment variable
GRAILS_GRADLE_HOME. It must be set to the location of a Gradle installation. If it is present is used as the Gradle version by Grails. In the following example we use this environment variable to force Grails to use Gradle 2.10: