Why doesn't ClassLoader::getResource return null, but Class::getResource returns a correct one

Question

I wrote the following simple program:

public class Test {
    public static void main(String[] args) throws IOException {
        System.out.println(get(Test.class.getResource("/c.conf"))); //fine
        System.out.println(
               get(Test.class.getClassLoader().getResource("/c.conf"))
        ); //NPE, Test.class.getClassLoader().getResource("/c.conf") returns null
    }

    public static String get(URL url) throws IOException {
        InputStreamReader reader = new InputStreamReader(url.openStream());
        StringBuilder sb = new StringBuilder();
        int current;
        while ((current = reader.read()) != -1)
            sb.append((char) current);
        return sb.toString();
    }
}

So, I looked at the documentation of Class::getResource(String) and found this:

The rules for searching resources associated with a given class are implemented by the defining class loader of the class.

So I thought these two methods should have loaded the resource in the same way.

Why does Test.class.getClassLoader().getResource("/c.conf") throw NullPointerException whereas Test.class.getResource("/c.conf") does not?