How I can get class name that add in my class Path ? (Whitout use any library)

How I can get class name that add in my class Path ? for example : I have a package and in that package I have some classes. I need the name of that classes on run time.

package sample;

public class Sample{ }

-----------------------

package Test;

public class Test{

public static void main(String[] args){
     //?
}

}