code: private String derivePackageName(Service service, Document iddDoc) {
  
  		String packageName = service.getPackageName();
  		if (packageName == null) {
  			packageName = readNamespaceAttr(iddDoc);
  			if (packageName == null) {
  				throw new PluginException("Cannot find a package name "
  								+ "(not specified in plugin and no namespace in IDD");
  			}
  		}
  		return packageName;
  	}
docs: Package name comes from explicit plugin param (if set), else the namespace definition, else
  skream and die.
  <p>
  Having the plugin override allows backwards compatibility as well as being useful for
  fiddling and tweaking.