private static final String[] ERRORS = { "SuccessiveWord", "DoubleNegative" };
...

//draws the error nodes out from their validatornode
private ArrayList<Node> errorNodes(NodeList nodes)
    {
        this.errorList.clear();
        ArrayList<Node> res2 = new ArrayList<>();
        for (int i = 0; i < nodes.getLength(); i++) {
            Node currentNode = nodes.item(i);
            Node validatorNode = currentNode.getFirstChild();
            if (isError(validatorNode.getTextContent().trim())) {
                res2.add(validatorNode);
            }
        }
        return res2;
    }