ReflectionUtil getclasses not working for runnable jar

I am reading all the classes within a package: a.b.c.test using:

Class<?>[] classes = ReflectionUtil.getClasses("a.b.c.test");

This works when I run the main file through eclipse but fails when exported as runnable jar.

Manifest file contains the main class and dependencies plugin is used for the external jars. All other functionalities are working fine which shows that jar is created without any issue. I could see class files in the above folder but the code returns 0 values. I used eclipse export as well as maven plugin but no luck.