The code seems to be alright and it doesn't depend on the used OS (like it should be when using java). Instead there is just a missing part of the configuration in the pom.xml:
When you paste this inside the
<project>-Tag of the pom.xml, this adds the missing manifest to the jar.
If it doesn't work for you, I could also send you the compiled jar.
Edit: When the missing part was added to the file, the steps in one of the above posts (the first part of the posts with the bullet-list) where sufficient to get a working build.