I\'m using SpringBoot 1.4.2. I want to be able to launch my SpringBoot application from the command line, specifying additional, external jars that should also be component
You're using the wrong launcher. Support for loader.path and loader.main is provided by PropertiesLauncher but you're using JarLauncher.
loader.path
loader.main
PropertiesLauncher
JarLauncher