title: AbstractMethodError: gov.nih.nlm.ncbi.www.soap.eutils.EUtilsServiceStub
body: <p>Everyone, I'm a fresh man in building webservice applications. I am using <a href="http://www.ncbi.nlm.nih.gov/entrez/eutils/soap/v2.0/DOC/esoap_java_help.html" rel="nofollow">this example</a> to access the NCBI (National Center for Biotechnology Information) webservice API. But I am getting the error below when I try and access the data.</p>
  
  <p>Does anyone know how to solve this issue?</p>
  
  <pre><code>log4j:WARN No appenders could be found for logger (org.apache.axis2.description.AxisOperation).
  log4j:WARN Please initialize the log4j system properly.
  Exception in thread "main" java.lang.AbstractMethodError: gov.nih.nlm.ncbi.www.soap.eutils.EUtilsServiceStub$EGqueryRequest.serialize(Ljavax/xml/namespace/QName;Ljavax/xml/stream/XMLStreamWriter;)V
      at org.apache.axis2.databinding.ADBDataSource.serialize(ADBDataSource.java:90)
      at org.apache.axiom.om.impl.llom.OMSourcedElementImpl.internalSerialize(OMSourcedElementImpl.java:695)
      at org.apache.axiom.om.impl.util.OMSerializerUtil.serializeChildren(OMSerializerUtil.java:563)
      at org.apache.axiom.om.impl.llom.OMElementImpl.internalSerialize(OMElementImpl.java:874)
      at org.apache.axiom.soap.impl.llom.SOAPEnvelopeImpl.serializeInternally(SOAPEnvelopeImpl.java:283)
      at org.apache.axiom.soap.impl.llom.SOAPEnvelopeImpl.internalSerialize(SOAPEnvelopeImpl.java:245)
      at org.apache.axiom.om.impl.llom.OMSerializableImpl.serializeAndConsume(OMSerializableImpl.java:193)
      at org.apache.axis2.transport.http.SOAPMessageFormatter.writeTo(SOAPMessageFormatter.java:74)
      at org.apache.axis2.transport.http.AxisRequestEntity.writeRequest(AxisRequestEntity.java:84)
      at org.apache.commons.httpclient.methods.EntityEnclosingMethod.writeRequestBody(EntityEnclosingMethod.java:499)
      at org.apache.commons.httpclient.HttpMethodBase.writeRequest(HttpMethodBase.java:2114)
      at org.apache.commons.httpclient.HttpMethodBase.execute(HttpMethodBase.java:1096)
      at org.apache.commons.httpclient.HttpMethodDirector.executeWithRetry(HttpMethodDirector.java:398)
      at org.apache.commons.httpclient.HttpMethodDirector.executeMethod(HttpMethodDirector.java:171)
      at org.apache.commons.httpclient.HttpClient.executeMethod(HttpClient.java:397)
      at org.apache.axis2.transport.http.AbstractHTTPSender.executeMethod(AbstractHTTPSender.java:621)
      at org.apache.axis2.transport.http.HTTPSender.sendViaPost(HTTPSender.java:193)
      at org.apache.axis2.transport.http.HTTPSender.send(HTTPSender.java:75)
      at org.apache.axis2.transport.http.CommonsHTTPTransportSender.writeMessageWithCommons(CommonsHTTPTransportSender.java:404)
      at org.apache.axis2.transport.http.CommonsHTTPTransportSender.invoke(CommonsHTTPTransportSender.java:231)
      at org.apache.axis2.engine.AxisEngine.send(AxisEngine.java:443)
      at org.apache.axis2.description.OutInAxisOperationClient.send(OutInAxisOperation.java:406)
      at org.apache.axis2.description.OutInAxisOperationClient.executeImpl(OutInAxisOperation.java:229)
      at org.apache.axis2.client.OperationClient.execute(OperationClient.java:165)
      at gov.nih.nlm.ncbi.www.soap.eutils.EUtilsServiceStub.run_eGquery(EUtilsServiceStub.java:1578)
      at edu.yale.pubmed.service.Client.CallEGQuery(Client.java:26)
      at edu.yale.pubmed.service.Client.main(Client.java:10)
  </code></pre>