final Class<?> clazz = Thread.currentThread().getContextClassLoader().loadClass("javax.websocket.server.ServerEndpointConfig$Configurator");
final Field f = clazz.getDeclaredField("defaultImpl");
final boolean acc = f.isAccessible();
f.setAccessible(true);
try {
f.set(null, new JavaEEDefaultServerEnpointConfigurator(instanceManagers));
} finally {
f.setAccessible(acc);
}
} catch (final ClassNotFoundException cnfe) {
// no-op