PI Java Mapping NullPointerException

Question

Hi Gurus,
I'm having some troubles doing the mapping through java mapping in PI.
I've done the java class in the SAP NWDS and imported it on PI through the ESR.
Now i'm trying to test through the SOAP and i've found the following error in the "Communication Channel Monitor":
500   Internal Server Error  SAP NetWeaver Application Server/Java AS 
java.lang.NullPointerException: while trying to invoke the method com.sap.aii.af.sdk.xi.lang.Binary.getBytes() of a null object returned from com.sap.aii.af.sdk.xi.mo.xmb.XMBPayload.getContent()
And the following error in the SXMB_MONI:
<SAP:Category>XIServer</SAP:Category>
  <SAP:Code area="INTERNAL">CLIENT_SEND_FAILED</SAP:Code>
  <SAP:P1>500</SAP:P1>
  <SAP:P2>Internal Server Error</SAP:P2>
  <SAP:P3>(See attachment HTMLError for details)</SAP:P3>
  <SAP:P4 />
  <SAP:AdditionalText />
  <SAP:Stack>Error while sending by HTTP (error code: 500 , error text: Internal Server Error) (See attachment HTMLError for details)</SAP:Stack>
I've developed the code below:
public class PI_Mapping_IF extends AbstractTransformation {
  public void transform(TransformationInput in, TransformationOutput out)    throws StreamTransformationException  {  
  this.execute(in.getInputPayload().getInputStream(), out.getOutputPayload().getOutputStream()); 
  public void execute(InputStream in, OutputStream out)  throws StreamTransformationException { 
  try  
  // Inicio do java mapping
  getTrace().addInfo("JAVA Mapping Iniciado"); //Log para o PI/XI
  // Declarações referentes ao XML de entrada
  DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
  DocumentBuilder db = dbf.newDocumentBuilder();
  Document xml_in = db.parse(in);
  // Declarações referentes ao XML de saída
  Document xml_out = db.newDocument();
  TransformerFactory transformerFactory = TransformerFactory.newInstance();
  Transformer transformer = transformerFactory.newTransformer();
  // Remove o standalone
  xml_in.setXmlStandalone(true);
  // Declara a estrutura que a RFC irá receber
  Element root = xml_out.createElement("ns1:ZFSD_VMOI_UPLOAD_CF_PG");
  root.setAttribute("xmlns:ns1","urn:sap-com:document:sap:rfc:functions");
  xml_out.appendChild(root);
  Element i_cenario = xml_out.createElement("I_CENARIO");
  root.appendChild(i_cenario);
  Element t_input = xml_out.createElement("T_INPUT");
  root.appendChild(t_input);
  Element item = xml_out.createElement("ITEM");
  t_input.appendChild(item);
  Element STRING = xml_out.createElement("STRING");
  item.appendChild(STRING);
  Element t_return = xml_out.createElement("T_RETURN");
  root.appendChild(t_return);
  Element item_r = xml_out.createElement("ITEM");
  t_return.appendChild(item_r);
  Element message = xml_out.createElement("MESSAGE");
  item_r.appendChild(message);
  // Verifica se existe algum filho no nó
  NodeList nodos = xml_in.getChildNodes(); 
  if (nodos.item(0) != null)
  getTrace().addInfo("O nó(XML) possui filhos"); //Log para o PI/XI
  // Declaração de variáveis
  String ident = ""; // <Ident>
  String buyer = ""; // <BuyerLineItemNum>
  String result = ""; // <Ident>;<BuyerLineItemNum>;<Date>;<QuantityValue>
  // Inicia a extração das informações do XML
  try{
  // Recupera o nó ShipToParty
  NodeList nodeShip = xml_in.getElementsByTagName("ns0:ShipToParty");
  Node node = nodeShip.item(0);
  Element elemXML = (Element) node;
  try{
  NodeList nodeIdent = elemXML.getElementsByTagName("ns0:Ident");
  Element nameElement = (Element) nodeIdent.item(0);
  nodeIdent = nameElement.getChildNodes();
  // Recupera o valor da chave <Ident>
  ident = PI_Mapping_IF.VerifyNull(((Node) nodeIdent.item(0)).getNodeValue());
  }catch(Exception e){
  result += "0.0;";
  // Recupera o nó ListOfMaterialGroupedPlanningDetail
  NodeList nodeBuyer  = xml_in.getElementsByTagName("ns0:MaterialGroupedPlanningDetail");
  for (int i = 0; i < nodeBuyer.getLength(); i++) {
  node = nodeBuyer.item(i);
  elemXML = (Element) node;
  try{
  // Preenche a chave BuyerLineItemNum
  NodeList nodeBuyerLine = elemXML.getElementsByTagName("ns0:BuyerLineItemNum");
  Element elemBuyerLine = (Element) nodeBuyerLine.item(0);
  nodeBuyerLine = elemBuyerLine.getChildNodes();
  buyer = PI_Mapping_IF.VerifyNull(((Node) nodeBuyerLine.item(0)).getNodeValue());
  }catch(Exception e){
  buyer += "0;";
  result = ident+";"+buyer+";";
  Node nodeDt_Qnt = nodeBuyer.item(i);
  Element elemDt_Qnt = (Element)nodeDt_Qnt;
  NodeList nodeValores = elemDt_Qnt.getElementsByTagName("ns0:ScheduleDetail");
  for (int j = 0; j < nodeValores.getLength(); j++) {
  node = nodeValores.item(j);
  elemXML = (Element) node;
  try{
  // Preenche a chave Date
  NodeList modelExtra = elemXML.getElementsByTagName("ns0:Date");
  Element extraElement = (Element) modelExtra.item(0);
  modelExtra = extraElement.getChildNodes();
  result += PI_Mapping_IF.VerifyNull(((Node) modelExtra.item(0)).getNodeValue())+";";
  }catch(Exception e){
  result += "//;";
  try {
  // Preenche a chave QuantityValue
  NodeList modelURL = elemXML.getElementsByTagName("ns0:QuantityValue");
  Element urlElement = (Element) modelURL.item(0);
  modelURL = urlElement.getChildNodes();
  result += PI_Mapping_IF.VerifyNull(((Node) modelURL.item(0)).getNodeValue())+";";
  } catch (Exception e) {
  result += "0.0;";
  // Marca o final do registro
  result += "||";
  // Preenche os nós itens
  Text srcxml = xml_out.createTextNode(result);
  STRING.appendChild(srcxml);
  result = "";
  buyer = "";
  }catch(Exception e){
  // Remove o standalone
  xml_out.setXmlStandalone(true);
  // Preenche o Cenario
  Text cenario = xml_out.createTextNode("P&G");
  i_cenario.appendChild(cenario);
  // Preenche mensagem de retorno
  Text msgxml = xml_out.createTextNode("XML lido com sucesso!");
  message.appendChild(msgxml);
  // Escreve a saida do XML            
  transformer.transform(new DOMSource(xml_out), new StreamResult(out));
  getTrace().addInfo("Fim da execução do Java Mapping");
  } catch (ParserConfigurationException e) {
  getTrace().addWarning(e.getMessage());
  throw new StreamTransformationException("Can not create DocumentBuilder.", e);
  } catch (SAXException e) {
  e.printStackTrace();
  } catch (IOException e) {
  e.printStackTrace();
  } catch (TransformerConfigurationException e) {
  e.printStackTrace();
  } catch (TransformerException e) {
  e.printStackTrace();
Am i doing anything wrong in the code? Where can this nullpointerexception be triggered?
Thanks.

Answer 1

These three xml are the same:
<?xml version="1.0"?><a:xml xmlns:a="urn:123">root</a:xml>
<?xml version="1.0"?><xml xmlns="urn:123">root</xml>
<?xml version="1.0"?><ns0:xml xmlns:ns0="urn:123">root</ns0:xml>
But your code will work only with last one, because it doesn't bound namespace to prefix ns0.