This is a skeleton of OpenRefine extension for SPARQL import, in the form of an independent Maven project. It works with OpenRefine 3.5.2
Run
mvn package
This creates a zip file in the target folder, which can then be installed in OpenRefine.
To avoid having to unzip the extension in the corresponding directory every time you want to test it, you can also use another set up: simply create a symbolic link from your extensions folder in OpenRefine to the local copy of this repository. With this setup, you do not need to run mvn package when making changes to the extension, but you will still to compile it with mvn compile if you are making changes to Java files, and restart OpenRefine if you make changes to any files.