This is a file dependency. A file dependency is specifically a binary file on disk without any metadata such as dependencies.
There’s no way to download dependencies from just a JAR file. If you just have a JAR file, you must declare any dependencies that it needs.
You need metadata in order to have dependencies resolved from Maven Central. This metadata is normally contained in a POM file as there are no dependencies from Maven Central present in the JAR file itself.
It is not possible to provide this POM with a file dependency or flatDir repository even if you publish it with the JAR file. You would need to have a folder on disk that is structured and configured as a Maven repository, even if it is on your local file system.