How to package a given folder
If you need to add to the jar file the contents of a given folder, you can use the option -C (capital alphabet C).
For example, the command jar -cf app.jar -C bin . will go to the bin folder, and add all of its contents to the jar file app.jar.
For example, the command jar -cf app.jar -C bin . will go to the bin folder, and add all of its contents to the jar file app.jar.