I have a standalone java project. I have performed a maven clean install. I now go into the target\\classes folder via command prompt and set all the required files in class
When you use -jar this is the sole mechanism setting the classpath for the program.
You must either have all the jars you need listed in the Class-Path line in the manifest (which implies they need to be findable in the local file system) or create a custom class loader capable of locating the jar you need.