tree.addStartElement(BaseResource.pr_error);
tree.startContent();
tree.addStartElement(BaseResource.pr_code);
tree.startContent();
tree.addText("" + status.getCode());
tree.addEndElement();
tree.addStartElement(BaseResource.pr_message);
tree.startContent();
tree.addText("Bad request: " + exceptionMessage(status.getThrowable()));
tree.addEndElement();
tree.addEndElement();