Creating an executable jar with groovy script

Question

I have a groovy script Automate.groovy. The script does not have a class definition or a main method. I am looking for the simplest way to create a jar containing the script. I tried compiling the groovy script using the following command:

groovyc Automate.groovy

I also have a Manifest file manifest-addition.txt that specifies the main class

Main-Class: Automate

And I created the jar using the command:

jar cvfm Automate.jar mainfest-addition.txt *.class

This gave me a jar with Automate.class and Automate$1.class and a Manifest file with the Main class. But when I tried to run the jar using java -jar Automate.jar I always get the error

cannot find or load main class Automate.

What am I doing wrong here?

There should be a simple way like this to create the jar. I just have this one script file that I want in my jar and I do not want to use maven/ant/gradle to get this job done. Isn't there a simple and straightforward way to do this?

Answer 1

The class file has dependencies on Groovy. Using the embeddable jar will fix the problem.

Using Groovy 2.4.5, if I have this script for Automate.groovy

println "Hello from Automate.groovy"

and use this manifest.txt:

Main-class: Automate
Class-path: jar/groovy-all-2.4.5.jar

and this simple build script:

rm *.class
groovyc Automate.groovy
jar cvfm Automate.jar manifest.txt Automate.class

and, in the run directory, I perform this:

bash$ mkdir jar
bash$ cp $GROOVY_HOME/embeddable/groovy-all-2.4.5.jar jar

then this works:

bash$ java -jar Automate.jar 
Hello from Automate.groovy

The solution will be much better if the embeddable jar is included in the Automate.jar itself. An example of that, using Gradle, is this project.