how to fill a composite object using java reflection?

I have a config file like this:

Provider Search,ConfigURL,http://myUrl

I want to fill this object using reflection

public class MyPrefrences {

    public ProviderSearch ProviderSearch;
}



    public class ProviderSearch {

        public String ConfigURL;

    }

here is my code, but I fail to set the composite object:

    MyPrefrences myPrefrences = new MyPrefrences();

    try {
        Field field = myPrefrences.getClass().getDeclaredField(normalizedCategory);
        Field field2 = field.getClass().getDeclaredField(normalizedKey);
        field2.set(field, val);
    } catch (Exception ex) {
        throw new RuntimeException(ex);
    }

how would you do it

a) if all leaves members are String?

b) if I the leaves can be primitives and non-primitives?