+ " is not an instance of org.exist.xpath.Module.");
+ " is not an instance of org.exist.xquery.Module.");
	public void loadBuiltInModule(String namespaceURI, String moduleClass) {		if (modules.containsKey(namespaceURI)) {			LOG.debug("module " + namespaceURI + " is already present");			return;		}		try {			Class mClass = Class.forName(moduleClass);			if (!(Module.class.isAssignableFrom(mClass))) {				LOG.warn(					"failed to load module. "						+ moduleClass						+ " is not an instance of org.exist.xpath.Module.");				return;			}			Module module = (Module) mClass.newInstance();			if (!module.getNamespaceURI().equals(namespaceURI)) {				LOG.warn("the module declares a different namespace URI. Skipping...");				return;			}			if (getPrefixForURI(module.getNamespaceURI()) == null				&& module.getDefaultPrefix().length() > 0)				declareNamespace(module.getDefaultPrefix(), module.getNamespaceURI());			modules.put(module.getNamespaceURI(), module);			//LOG.debug("module " + module.getNamespaceURI() + " loaded successfully.");		} catch (ClassNotFoundException e) {			//LOG.warn("module class " + moduleClass + " not found. Skipping...");		} catch (InstantiationException e) {			LOG.warn("error while instantiating module class " + moduleClass, e);		} catch (IllegalAccessException e) {			LOG.warn("error while instantiating module class " + moduleClass, e);		}	}