Java.lang.NullPointerException returned from webservice

Question

Hi I have an axis client which sends an image attachment to an axis webservice, however I am returned with a null pointer exception,
this is my client,
package chapter5;
import java.net.URL;
import org.apache.axis.client.Service;
import org.apache.axis.client.Call;
import org.apache.axis.encoding.XMLType;
import org.apache.axis.encoding.ser.JAFDataHandlerSerializerFactory;
import org.apache.axis.encoding.ser.JAFDataHandlerDeserializerFactory;
import javax.xml.rpc.ParameterMode;
import javax.xml.rpc.namespace.QName;
import javax.activation.DataHandler;
import javax.activation.FileDataSource;
public class AttachmentServiceClient{
     public AttachmentServiceClient(){}
     public static void main(String args[]){
          try{
               String filename = "D:\\images\\products\\r.jpg";
               //create the data for the attached file
               DataHandler dhSource = new DataHandler(new FileDataSource(filename));
               String endpointURL = "http://localhost:8080/axis/services/AttachmentService";
               String methodName = "addImage";
               Service service = new Service();
               Call call = (Call)service.createCall();
               call.setTargetEndpointAddress(new URL(endpointURL));
               call.setOperationName(new QName("AttachmentService",methodName));
               call.addParameter("sku",XMLType.XSD_STRING,ParameterMode.PARAM_MODE_IN);
               QName qname = new QName("AttachmentService","DataHandler");
               call.addParameter("image",qname,ParameterMode.PARAM_MODE_IN);
               //register the datahandler
               call.registerTypeMapping(dhSource.getClass(),qname,JAFDataHandlerSerializerFactory.class,JAFDataHandlerDeserializerFactory.class);
               call.setReturnType(XMLType.XSD_STRING);
               Object[] params = new Object[]{"SKU-111",dhSource};
               String result = (String)call.invoke(params);
               System.out.println("The response: "+result);
;          }catch(Exception e){
               System.err.println(e.toString());
this is my webservice,
package chapter5;
import javax.activation.DataHandler;
import java.io.FileOutputStream;
import java.io.File;
import java.io.BufferedInputStream;
public class SparePartAttachmentService{
     public SparePartAttachmentService(){}
     public String addImage(String sku,DataHandler dataHandler){
          System.out.println("trying");
          try{
               String filepath = "c:/wrox-axis/"+sku+"-image.jpg";
               FileOutputStream fout = new FileOutputStream(new File(filepath));
               BufferedInputStream in = new BufferedInputStream(dataHandler.getInputStream());
               while(in.available()!=0){
                    fout.write(in.read());
          }catch(Exception e){
               return e.toString();
          return "Image: "+sku+" has been added successfully!!";
I did a test by stripping out the attachment being sent by the client and just let it send the string,
then in the webservice I stripped out the lines for the attachment and just returned the string and it worked ok, so it has been deployed correctly.
I have the Java Activation framework both in tomcat commons and my webapps lib dir.
I'm pretty sure the error is being thrown here,
public String addImage(String sku,DataHandler dataHandler){
any help would be greatly appreciated,
thank you,
JP.

Answer 1

Ok, I have now successfully got the stack trace to show where the exception bubbled, Im suprised its in the axis client as I assumed it was in the webservice, but this whole exercise has been extremely beneficial,
anyway this is the client code again and the stack trace error, I now think the problem lies within the JAF, possibly, however, im doing something incorrectly,
package chapter5;
import java.net.URL;
import org.apache.axis.client.Service;
import org.apache.axis.client.Call;
import org.apache.axis.encoding.XMLType;
import org.apache.axis.encoding.ser.JAFDataHandlerSerializerFactory;
import org.apache.axis.encoding.ser.JAFDataHandlerDeserializerFactory;
import javax.xml.rpc.ParameterMode;
import javax.xml.rpc.namespace.QName;
import javax.activation.DataHandler;
import javax.activation.FileDataSource;
import javax.activation.DataSource;
import java.io.File;
public class AttachmentServiceClient{
     public AttachmentServiceClient(){}
     public static void main(String args[]){
          try{
               String filename = "D:\\javaDev\\utilities\\coldfusionMX\\Java\\javapetstore\\r.jpg";
               //create the data for the attached file
               DataHandler dhSource = new DataHandler(new FileDataSource(new File(filename)));
               String endpointURL = "http://localhost:8080/axis/services/AttachmentService";
               String methodName = "addImage";
               Service service = new Service();
               Call call = (Call)service.createCall();
               call.setTargetEndpointAddress(new URL(endpointURL));
               call.setOperationName(new QName("AttachmentService",methodName));
               call.addParameter("sku",XMLType.XSD_STRING,ParameterMode.PARAM_MODE_IN);
               QName qname = new QName("AttachmentService","DataHandler");
               call.addParameter("image",qname,ParameterMode.PARAM_MODE_IN);
               //register the datahandler
               call.registerTypeMapping(dhSource.getClass(),qname,JAFDataHandlerSerializerFactory.class,JAFDataHandlerDeserializerFactory.class);
               call.setReturnType(XMLType.XSD_STRING);
               Object[] params = new Object[]{"SKU-111",dhSource};
               try{
                    String result = (String)call.invoke(params);
                    System.out.println("The response: "+result);
               }catch(Exception f){
                    f.getStackTrace();
                    f.printStackTrace();
          }catch(Exception e){
               System.err.println("error");
stack trace
C:\wrox-axis>java chapter5.AttachmentServiceClient
java.lang.NullPointerException
at org.apache.axis.AxisFault.makeFault(Unknown Source)
at org.apache.axis.SOAPPart.getAsString(Unknown Source)
at org.apache.axis.SOAPPart.getAsBytes(Unknown Source)
at org.apache.axis.Message.getContentLength(Unknown Source)
at org.apache.axis.transport.http.HTTPSender.invoke(Unknown Source)
at org.apache.axis.strategies.InvocationStrategy.visit(Unknown Source)
at org.apache.axis.SimpleChain.doVisiting(Unknown Source)
at org.apache.axis.SimpleChain.invoke(Unknown Source)
at org.apache.axis.client.AxisClient.invoke(Unknown Source)
at org.apache.axis.client.Call.invoke(Unknown Source)
at org.apache.axis.client.Call.invoke(Unknown Source)
at org.apache.axis.client.Call.invoke(Unknown Source)
at org.apache.axis.client.Call.invoke(Unknown Source)
at chapter5.AttachmentServiceClient.main(AttachmentServiceClient.java:45
Caused by: java.lang.NullPointerException
at org.apache.axis.encoding.ser.JAFDataHandlerSerializer.serialize(Unkno
wn Source)
at org.apache.axis.encoding.SerializationContextImpl.serializeActual(Unk
nown Source)
at org.apache.axis.encoding.SerializationContextImpl.serialize(Unknown S
ource)
at org.apache.axis.encoding.SerializationContextImpl.outputMultiRefs(Unk
nown Source)
at org.apache.axis.message.SOAPEnvelope.outputImpl(Unknown Source)
at org.apache.axis.message.MessageElement.output(Unknown Source)
... 13 more