Is it a good idea to replace java.net.URL URLStreamHandlerFactory using reflection?

In Java we can register a custom protocol handler in at least two ways:

1. by setting system property 'java.protocol.handler.pkgs'
2. using URL.setURLStreamHandlerFactory

For more details please check http://ift.tt/1QbLzBO

I can not go with the first option, as i would have to add a lot of jar files to the server (tomcat) classpath, to make the handler implementaion visible for bootstrap classloader. Moreover some initialization is needed, which has to be done in an application context.

The problem with the second option is that the Factory can be registered only once (check java.net.URL#setURLStreamHandlerFactory), and unfortunately it is done by Tomcat.

What i can do is to create a decorator factory which will extend the existing one by my protocol handler. Than using relfection set the static field URL#factory to null and register (again?) my "decoratorFactory" in a standard way using URL#setURLStreamHandlerFactory. I'm just wondering if it is a good idea to use the reflection here...? How about the security?

I would like to do something like that:

try {
        Field factoryField = URL.class.getDeclaredField("factory");
        factoryField.setAccessible(true);
        //  get current factory
        Object currentFactory = factoryField.get(null);
        //  define a decorator factory
        MyFactoryDecorator mfd = new MyFactoryDecorator(currentFactory);
        //  set the factory to null and register MyFactoryDecorator using URL#setURLStreamHandlerFactory.
        factoryField.set(null, null);
        URL.setURLStreamHandlerFactory(mfd);
    } catch (NoSuchFieldException e) {
        e.printStackTrace();
    } catch (IllegalAccessException e) {
        e.printStackTrace();
    }