Loading a remote Java class

I built an android app.

I use an advertising platform, but I'm not sure I would like to stick to it (maybe I'll decide to change it later).

For this purpose, I would like to create an interface, and a class implementing it, calling the ads of the platform.

The idea is that I could later at some point, load another class file from my server (with reflection) replacing the previous one. That way, I will be able to change advertising platform "on the fly" (for instance - Admob/Airpush).

Does someone know how can I load remote classes with Java?

Do you have any code example the shows it?

Solution

You need to create your own ClassLoader, give a look at How to use URLClassLoader to load a *.class file?

Here is an example (from http://www.programcreek.com/java-api-examples/index.php?api=java.net.URLClassLoader, there is others with hosted urls):

private void invokeClass(String path, String name, String[] args) throws
        ClassNotFoundException,
        NoSuchMethodException,
        InvocationTargetException,
        MalformedURLException,
        InterruptedException,
        IllegalAccessException {
    File f = new File(path);
    URLClassLoader u = new URLClassLoader(new URL[]{f.toURI().toURL()});
    Class c = u.loadClass(name);
    Method m = c.getMethod("main", new Class[]{args.getClass()});
    m.setAccessible(true);
    int mods = m.getModifiers();
    if (m.getReturnType() != void.class || !Modifier.isStatic(mods) || !Modifier.isPublic(mods)) {
        throw new NoSuchMethodException("main");
    }
    m.invoke(null, new Object[]{args});
    m = null;
    System.gc(); // uh-oh
}