src/main/java/org/jboss/util/xml/catalog/helpers/Namespaces.java
public static String getNamespaceURI(Element element) {
	String prefix = getPrefix(element);
	return getNamespaceURI(element, prefix);
    }
public static String getNamespaceURI(Element element) {
	String prefix = getPrefix(element);
	return getNamespaceURI(element, prefix);
    }
Returns the namespace URI for the namespace to which the
element belongs.

@param element The element.
@return The namespace URI associated with the namespace of the
element, or null if no namespace declaration exists for it.