code: protected boolean equalsNamespace(Node control, Node test) {
          String controlNS = control.getNamespaceURI();
          String testNS = test.getNamespaceURI();
          if (controlNS == null) {
              return testNS == null;
          }
          return controlNS.equals(testNS);
      }
docs: Determine whether two nodes are defined by the same namespace URI
  @param control
  @param test
  @return true if the two nodes are both defined by the same namespace URI
  (including the default - empty - namespace), false otherwise