JMRI AppleScript Support is an easy way to add the AppleScript scripting language available on macOS to an application that supports scripting via the Java scripting API.
Java versions 7 and 8 for macOS include AppleScript support, but do not advertise it to Java applications. This JAR advertises that support to Java applications running on macOS under Java 1.7 or 1.8.
Java version 9 drops AppleScript support entirely, so this JAR provides no benefits on that version of Java.