Load and instantiate class from jar in class search path

I am looking for a way to instantiate an object from a jar file in my class search path, i know the name of the class and the parent class it extends and the interface it implements, unfortunatelly i have not been able to find a solution so far. So, suppose the following:

interface Modifier{
 //is basically just a flag
}

Then:

public class ModifierImpl implements Modifier{
 //some methods
}

Then:

public class CustomModifierImpl extends ModifierImpl{
    //some implementation here
    }

Those interfaces/classes are into a jar that i import dinamically in my project and then i would like to instantiate an instance of CustomModifierImpl

Since i know that the class Class is generic, i thought that something like so would be possible, but its not:

private Class<ModifierImpl> loadClass(String fullClassName) {
    Class<ModifierImpl> clazz;
    try {
        clazz= urlLoader.loadClass(fullClassName);
    } catch (ClassNotFoundException e) {
        return null;
    }
    return clazz;
}

I get a type mismatch when i do this, is there any other way i can achieve this? i would not like to work with an instance of Class<?> all around my program as i would probably need to do dozens of casts.

This will also not work:

private Class<ModifierImpl> loadClass(String fullClassName) {
    Class<ModifierImpl> clazz;
    try {
        clazz= urlLoader.loadClass(fullClassName).cast(clazz);
    } catch (ClassNotFoundException e) {
        return null;
    }
    return clazz;
}

Thank you

Solution

to load class from .class file

File file2 = new File  ("c:\\myclasses\\");

// Convert File to a URL
URL url = file2.toURL();          // file:/c:/myclasses/
 URL[] urls = new URL[]{url};

// Create a new class loader with the directory
ClassLoader cl = new URLClassLoader(urls);

 // Load in the class; 
 Class cls = cl.loadClass("test.MyClass");

to get the class:

Class aClass;
ClassLoader classLoader = test.class.getClassLoader();
try {
    aClass = classLoader.loadClass(fullClassName);
   } catch (ClassNotFoundException e) {
   e.printStackTrace();
 }

once you have the class, you can instantiate it:

Class<?> clazz = Class.forName(fullClassName);
Constructor<?> constructor = clazz.getConstructor();
Object result = constructor.newInstance();