I am using JavaFX in the Felix OSGI container from Apache. JavaFX is not a bundle and is just part of the main classloader just as the normal JRE is. It seems that the WebView component is trying to register a URL handler, however there can be only one and Felix has already registered one. Ideally WebView should not register any URL handler in this way since it is a system library (well I expect it to be part of the JDK at some point) and having a system library use the URL.setURLStreamHandlerFactory basically means that this function is not available to anyone at this point. As a workaround a switch to disable the registration in the WebView component is also a possibility since it does not seem that this is critical for the component to have it. Following severe log is received when the WebView component is first created.

30-06-2011 10:55:04 com.sun.webpane.webkit.network.WebkitStreamHandlerFactoryProvider registerStreamHandlerFactory
SEVERE: null