How to scan methods in all classes of a java application in runtime and call those methods according to the given request?

I want to implement REST api implementation for an old ERP system bounded to JAVA EE and JDK 1.8. It is not Spring. I want to create a servlet responsible for controlling requests with "/Rest/" path.

I want to find a suitable library for routing requests to classes. for example if a request comes with this URL : "BASEURL/Rest/com/humanresourse/apis/MCOMBPARTNER/save", the process should search in all jar files included in project in runtime and finds the package "com.humanresource.api" and in that finds the "MCOMBPARTNER" class and then calls the "save" method of it.

I don't want to use delegation or write a simple code I want to know best libraries that can help me doing this task in an enterprise way. Thanks