code: @Override
      public final void normalize() {
          Node next;
          for (Node node = getFirstChild(); node != null; node = next) {
              next = node.getNextSibling();
              node.normalize();
  
              if (node.getNodeType() == Node.TEXT_NODE) {
                  ((TextImpl) node).minimize();
              }
          }
      }
docs: Normalize the text nodes within this subtree. Although named similarly,
  this method is unrelated to Document.normalize.