NoSuchMethodException exception when class is loaded via URLClassLoader

This question is slightly different from the previous error reported via Unable to invoke method by java reflection: NoSuchMethodException

Signature of overloading methods follow as below in target class, my objective is to invoke public List run(FileInput,StreamOutput)dynamically.

public List run(String, String);
public List run(FileInput,StreamOutput);

Case 1: When dynamically loading a method using reflection api when target class(jar) is present in CLASS_PATH - method is accessible.

    Class mapClass = loader.loadClass("com.sample.test.TrackingService");       
FileInput input = new FileInput(inputFileFullPath); 
StreamOutput output =  new StreamOutput(new java.io.ByteArrayOutputStream());

Object mapObj = mapClass.newInstance();
Class params[]={ FileInput.class,StreamOutput.class};
Method m = mapClass.getDeclaredMethod("run", params);

outputList = (List) m.invoke(mapObj, input,output);`

Case 2: On top of the same code in Case 1, instead of placing jar in CLASS_PATH, but loaded via URLClassLoader then it throws NoSuchMethodException

Code block

URL urls[] = {new URL("file:/opt/jars/Tracking.jar")};
URLClassLoader loader = new URLClassLoader(urls);
Class mapClass = loader.loadClass("com.sample.test.TrackingService",true,loader);       
FileInput input = new FileInput(inputFileFullPath); 
StreamOutput output =  new StreamOutput(new java.io.ByteArrayOutputStream());
Object mapObj = mapClass.newInstance();
Class params[]={ FileInput.class,StreamOutput.class};
Method m = mapClass.getDeclaredMethod("run", params);

outputList = (List) m.invoke(mapObj, input,output);

Exception is thrown at line Method m = mapClass.getDeclaredMethod("run", params);

Question 1: Is something missing here when loading class via URLClassLoader ?
Question 2: Any recommendation on loading class definition into JVM via custom class. I mean, achieving same level as jar file present in CLASS_PATH ? Part of our requirement and limitation we can't place jar under CLASS_PATH or add jar path to CLASS_PATH