When the main module is in the given --runtime-image, so no --module-path option is used even though --module option is used, LauncherData.createModule() will call a ModuleFinder with a path such as [, runtime\lib]
The empty string followed by comma causes ModuleFinder to look in the current dir.
If there is a non-modular jar in the current directory, (such as hello.jar) you can get an exception:
jdk.jpackage.internal.ConfigException: java.lang.module.FindException: Unable to derive module descriptor for hello.jar