rest-mock | REST API mocking using Node and JSON-defined responses | REST library

If you have volumes: that binds a host directory to a container directory, at container startup time, the contents of that host directory always completely hide anything that was in the underlying image. In your case, you're mounting a directory over the directory that contains the jar file, so the actual application gets hidden.

You should restructure your application to keep the data somewhere separate from the application code. Using simple top-level directories like /app and /data is common enough, or you can make the data directory a subdirectory of your application directory.

Once you've done this, you can change the volumes: mount to a different directory: