Groovy‘s RootLoader is a handy class that can be used to encapsulate a Groovy script’s reference to external classpath dependencies within the script itself. The documentation for RootLoader states, ...

JAVA_HOME is an operating system (OS) environment variable which can optionally be set after either the Java Development Kit (JDK) or the Java Runtime Environment (JRE) is installed. The JAVA_HOME ...

For Java-based programs such as Maven, Jenkins, Gradle or Tomcat to run, they need to know that Java's JDK is installed. That's the purpose of the JAVA_HOME environment variable. It tells programs ...