On 8/31/2018 12:04 AM, robertlazarski wrote:


On Thu, Aug 30, 2018 at 2:46 PM Alex Borschenko <aaborsche...@gmail.com <mailto:aaborsche...@gmail.com>> wrote:

    Hi All!

    I have deployed archive of services which consume/produce XMLs and
    now I'm trying to add one more service who will consume/produce JSON.
    It is simple service which operates with POJOs.

    To enable JSON operations I added to axis2.xml:

            <messageFormatter contentType="application/json"
    class="org.apache.axis2.json.gson.JsonFormatter" />

    <messageBuilder contentType="application/json"
    class="org.apache.axis2.json.gson.JsonBuilder" />

    In services XML I have declared my service:

    <service name="LoginWSManager">
        <Description>
            This is a sample service to test json implementation
        </Description>
        <messageReceivers>
            <messageReceiver mep="http://www.w3.org/ns/wsdl/in-out";
    <http://www.w3.org/ns/wsdl/in-out>
    class="org.apache.axis2.json.gson.rpc.JsonRpcMessageReceiver" />
            <messageReceiver mep="http://www.w3.org/ns/wsdl/in-only";
    <http://www.w3.org/ns/wsdl/in-only>
    class="org.apache.axis2.json.gson.rpc.JsonInOnlyRPCMessageReceiver"/>
        </messageReceivers>
        <parameter name="ServiceClass"
    locked="false">security.LoginWSManager</parameter>
    </service>

    Service code:

    public LoginResponseWSBean login(String email, String password)throws 
Exception {
         Application.logger().info("Logging in user email: " + email);

         final LoginResponseWSBean loginResponseWSBean =new 
LoginResponseWSBean();
         try {
             loginBusinessLogic.login(email, password);
         }catch (Exception e) {
             loginResponseWSBean.setLoggedIn(false);
             loginResponseWSBean.setMessage(e.getMessage());
             loginResponseWSBean.setStackTrace(ExceptionUtils.getStackTrace(e));
             Application.logger().warning(String.format("Returning: %s", 
loginResponseWSBean));
             return loginResponseWSBean;
         }
         loginResponseWSBean.setLoggedIn(true);
         loginResponseWSBean.setMessage(email +" logged in successfully!");

         return loginResponseWSBean;
    }

    public class LoginResponseWSBeanimplements Serializable {

         private boolean loggedIn =false;
         private Stringmessage ="";
         private StringstackTrace ="";

         public LoginResponseWSBean(boolean loggedIn, String message, String 
stackTrace) {
             this.loggedIn = loggedIn;
             this.message = message;
             this.stackTrace = stackTrace;
         }

         public LoginResponseWSBean() {

         }
    ....
    }


    When I call it by this command:

    curl -X POST -H "Content-Type: application/json" -d
    "{'login':[{'email':'em...@domain.com'}, {'password':'secret'}]}"
    
<mailto:%7B%27login%27:[%7B%27email%27:%27em...@domain.com%27%7D,%7B%27password%27:%27secret%27%7D]%7D>
    http://localhost:8080/axis2/services/LoginWSManager/login

    It responds with this message:
    
{"Fault":{"faultcode":"soapenv:Server","faultstring":"java.lang.NullPointerException","detail":""}}

    In tomcat logs I can see this stacktrace:

    30-Aug-2018 23:38:09.137 INFO [http-nio-8080-exec-9]
    org.apache.catalina.core.StandardWrapperValve.invoke [ERROR]
    java.lang.NullPointerException
            at
    org.apache.axis2.context.MessageContext.isFault(MessageContext.java:4304)
            at
    
org.apache.axis2.transport.http.CommonsHTTPTransportSender.sendUsingOutputStream(CommonsHTTPTransportSender.java:289)
            at
    
org.apache.axis2.transport.http.CommonsHTTPTransportSender.invoke(CommonsHTTPTransportSender.java:244)
            at
    org.apache.axis2.engine.AxisEngine.send(AxisEngine.java:431)
            at
    
org.apache.axis2.receivers.AbstractInOutMessageReceiver.invokeBusinessLogic(AbstractInOutMessageReceiver.java:43)
            at
    
org.apache.axis2.receivers.AbstractMessageReceiver.receive(AbstractMessageReceiver.java:106)
            at
    org.apache.axis2.engine.AxisEngine.receive(AxisEngine.java:169)
            at
    
org.apache.axis2.transport.http.HTTPTransportUtils.processHTTPPostRequest(HTTPTransportUtils.java:178)
            at
    org.apache.axis2.transport.http.AxisServlet.doPost(AxisServlet.java:163)
            at
    javax.servlet.http.HttpServlet.service(HttpServlet.java:648)
            at
    javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
            at
    
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:292)
            at
    
org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207)
            at
    org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
            at
    
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:240)
            at
    
org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207)
            at
    
org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:197)
            at
    
org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:106)
            at
    
org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:502)
            at
    
org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:141)
            at
    org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)
            at
    
org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:616)
            at
    
org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88)
            at
    org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:528)
            at
    
org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1100)
            at
    
org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:687)
            at
    
org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1520)
            at
    
org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1476)
            at
    
java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
            at
    
java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
            at
    
org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
            at java.lang.Thread.run(Thread.java:745)

    Please help me find out why it is not processing
    LoginResponseWSBean response object as expected and generates NPE.
    Thanx!

    Alex


I am planning on a patch for this issue as I am using GSON / Axis2 quite a bit in my day job right now. There are a few things I want to discuss with the Axis2 dev team here, including this NPE.

In this case I made this change in the MessageContext.java source. You would have to compile from source to fix it in the short term. I don't know why the Envelope is null here. Making this change had no effect on my existing soap based services but it did fix the GSON services.

    public boolean isFault() {
        if (getEnvelope() == null) {
            log.warn(getLogIDString() + ": ****WARNING**** " + myClassName +
                    " , found null envelope, returning false");
            return false;
        }
        return getEnvelope().hasFault();
    }

I was wondering if anyone is using GSON with axis2, the docs are something I plan on improving soon and good to know someone else is using this code.

Regards,
Robert

Hi Robert!

Your solution helped :)
I was already about to try this on my own and your suggestion made me stronger in my decision :)

Thanx, mate!

Alex.

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