This is /just great/ ...
JDK 1.5 changes the method signature of javax.naming.spi.ObjectFactory.getObjectInstance() from this:
public Object getObjectInstance(Object reference, Name name, Context ctx, Hashtable env)
to this:
public Object getObjectInstance(Object reference, Name name, Context ctx, Hashtable<String, ?> env)
AFAICT, this means that is now impossible to write an ObjectFactory that compiles in both JDK 1.4 and 1.5. Ugh.