I found this tip on Heroku devcenter website.
https://devcenter.heroku.com/articles/local-maven-dependencies
In a few words, you add a "repo" directory to your project, deploy your artifact into this local repo and declare this repository in your pom.xml. Then, you can use your local jar as classic maven dependency.
Here is the example :
It's just perfect! Thanks to the Heroku member who had this excellent idea!
https://devcenter.heroku.com/articles/local-maven-dependencies
In a few words, you add a "repo" directory to your project, deploy your artifact into this local repo and declare this repository in your pom.xml. Then, you can use your local jar as classic maven dependency.
Here is the example :
yourproject
+- pom.xml
+- src
+- repo
mvn deploy:deploy-file -Durl=file:///path/to/yourproject/repo/ -Dfile=mylib-1.0.jar -DgroupId=com.example -DartifactId=mylib -Dpackaging=jar -Dversion=1.0