Now that jigsaw is prohibiting deep reflection on types provided by the boot modules we are running into an issue with the ugly things we do [1] in order to support multiple factories in Equinox (an OSGi implementation). Each Equinox instance has its own context aware ContentHandlerFactory and URLStreamHandlerFactory which serves up handlers that are available for the particular instance of Equinox. In order to do this we have to resort to some very ugly reflection. This allows us to gain access to the 'base' factory object set in the VM so that each instance of the framework can register itself with the 'base' factory. The 'base' factory handlers do the complicated work of figuring out which factory to call based on the context which is calling the base handler.
We also resort to reflection on framework shutdown in order to flush our factories out from the VM so that the base factory is not pinning our framework in memory. I am also aware that the Apache Felix OSGi Framework implementation uses similar deep reflection in its implementation. Are there any plans in Java 9 that will make this scenario easier to achieve without resorting to the use of deep reflection on the URL types from the VM? If not, are there going to be command line options that will allow us to open up deep reflection of specific VM types as a compatibility mode until we can get a proper solution? At a minimum I think we need someway to unset the statically set handlers in the VM to avoid pinning our base factories. I can think of other non-reflective ways to gain access to the base handler instance in order to register each framework instance with the base handler. For example, the base factory could implement a specific protocol which allows a connection to register another framework. But we are still left with a delima of how to wrap the handlers returned by various framework factory instances from the base handlers. All the interesting methods on java.net.URLStreamHandler are protected. Even though the proxy base handler extends java.net.URLStreamHandler it is not allowed to call the protected methods on another instance of java.net.URLStreamHandler. We resorted to deep reflection on the java.net.URLStreamHandler class methods to do that. The java.net.URLStreamHandler class is not an interface so we cannot easily create proxy classes using java.lang.reflect.Proxy. Tom [1] https://bugs.eclipse.org/bugs/show_bug.cgi?id=502209
