I have two webservices A and B. A needs to invoke one of the webMethods in B. How can I achieve this? I am using maven's wsimport plugin to build A. This is to generate the necessary stubs for B and include them as part of the Webservice A. However, when I try to Invoke the webmethod o f B, I get an Exception. Can anyone please tell me what is going on? Below Is the code and the exception trace: Code:

BBeanService bbs = new BBeanService();
BBean bb = bbs.getBBeanPort();            
bb.invokeWebService(); // this is throwing exception

This is the exception trace:
java.lang.NullPointerException at com.sun.xml.ws.fault.SOAP11Fault.getProtocolException(SOAP11Fault.java:188) at com.sun.xml.ws.fault.SOAPFaultBuilder.createException(SOAPFaultBuilder.java:116) at com.sun.xml.ws.client.sei.SyncMethodHandler.invoke(SyncMethodHandler.java:119) at com.sun.xml.ws.client.sei.SyncMethodHandler.invoke(SyncMethodHandler.java:89) at com.sun.xml.ws.client.sei.SEIStub.invoke(SEIStub.java:118) at $Proxy175.getCase(Unknown Source) at com.kebok.ais.billing.server.ejb.impl.ChargeManagerBean.generateBillDetails(ChargeManagerBean.java:144) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:597) at com.sun.enterprise.security.application.EJBSecurityManager.runMethod(EJBSecurityManager.java:1011) at com.sun.enterprise.security.SecurityUtil.invoke(SecurityUtil.java:175) at com.sun.ejb.containers.BaseContainer.invokeTargetBeanMethod(BaseContainer.java:2920) at com.sun.ejb.containers.BaseContainer.intercept(BaseContainer.java:4011) at com.sun.ejb.containers.WebServiceInvocationHandler.invoke(WebServiceInvocationHandler.java:190) at $Proxy173.generateBillDetails(Unknown Source) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:597) at com.sun.enterprise.webservice.InvokerImpl.invoke(InvokerImpl.java:78) at com.sun.enterprise.webservice.EjbInvokerImpl.invoke(EjbInvokerImpl.java:82) at com.sun.xml.ws.server.InvokerTube$2.invoke(InvokerTube.java:146) at com.sun.xml.ws.server.sei.EndpointMethodHandler.invoke(EndpointMethodHandler.java:257) at com.sun.xml.ws.server.sei.SEIInvokerTube.processRequest(SEIInvokerTube.java:93) at com.sun.xml.ws.api.pipe.Fiber.__doRun(Fiber.java:595) at com.sun.xml.ws.api.pipe.Fiber.doRun(Fiber.java:554) at com.sun.xml.ws.api.pipe.Fiber.doRun(Fiber.java:539) at com.sun.xml.ws.api.pipe.Fiber.runSync(Fiber.java:436) at com.sun.xml.ws.api.pipe.helper.AbstractTubeImpl.process(AbstractTubeImpl.java:106) at com.sun.enterprise.webservice.MonitoringPipe.process(MonitoringPipe.java:147) at com.sun.xml.ws.api.pipe.helper.PipeAdapter.processRequest(PipeAdapter.java:115) at com.sun.xml.ws.api.pipe.Fiber._doRun(Fiber.java:595) at com.sun.xml.ws.api.pipe.Fiber.doRun(Fiber.java:554) at com.sun.xml.ws.api.pipe.Fiber.doRun(Fiber.java:539) at com.sun.xml.ws.api.pipe.Fiber.runSync(Fiber.java:436) at com.sun.xml.ws.api.pipe.helper.AbstractTubeImpl.process(AbstractTubeImpl.java:106) at com.sun.xml.ws.tx.service.TxServerPipe.process(TxServerPipe.java:317) at com.sun.enterprise.webservice.CommonServerSecurityPipe.processRequest(CommonServerSecurityPipe.java:222) at com.sun.enterprise.webservice.CommonServerSecurityPipe.process(CommonServerSecurityPipe.java:133) at com.sun.xml.ws.api.pipe.helper.PipeAdapter.processRequest(PipeAdapter.java:115) at com.sun.xml.ws.api.pipe.Fiber._doRun(Fiber.java:595) at com.sun.xml.ws.api.pipe.Fiber.doRun(Fiber.java:554) at com.sun.xml.ws.api.pipe.Fiber.doRun(Fiber.java:539) at com.sun.xml.ws.api.pipe.Fiber.runSync(Fiber.java:436) at com.sun.xml.ws.server.WSEndpointImpl$2.process(WSEndpointImpl.java:243) at com.sun.xml.ws.transport.http.HttpAdapter$HttpToolkit.handle(HttpAdapter.java:444) at com.sun.xml.ws.transport.http.HttpAdapter.handle(HttpAdapter.java:244) at com.sun.xml.ws.transport.http.servlet.ServletAdapter.handle(ServletAdapter.java:135) at com.sun.enterprise.webservice.Ejb3MessageDispatcher.handlePost(Ejb3MessageDispatcher.java:113) at com.sun.enterprise.webservice.Ejb3MessageDispatcher.invoke(Ejb3MessageDispatcher.java:87) at com.sun.enterprise.webservice.EjbWebServiceServlet.dispatchToEjbEndpoint(EjbWebServiceServlet.java:228) at com.sun.enterprise.webservice.EjbWebServiceServlet.service(EjbWebServiceServlet.java:157) at javax.servlet.http.HttpServlet.service(HttpServlet.java:847) at com.sun.enterprise.web.AdHocContextValve.invoke(AdHocContextValve.java:114) at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:648) at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:593) at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:587) at com.sun.enterprise.web.WebPipeline.invoke(WebPipeline.java:87) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:222) at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:648) at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:593) at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:587) at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:1096) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:166) at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:648) at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:593) at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:587) at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:1096) at org.apache.coyote.tomcat5.CoyoteAdapter.service(CoyoteAdapter.java:288) at com.sun.enterprise.web.connector.grizzly.DefaultProcessorTask.invokeAdapter(DefaultProcessorTask.java:647) at com.sun.enterprise.web.connector.grizzly.DefaultProcessorTask.doProcess(DefaultProcessorTask.java:579) at com.sun.enterprise.web.connector.grizzly.DefaultProcessorTask.process(DefaultProcessorTask.java:831) at com.sun.enterprise.web.connector.grizzly.DefaultReadTask.executeProcessorTask(DefaultReadTask.java:341) at com.sun.enterprise.web.connector.grizzly.DefaultReadTask.doTask(DefaultReadTask.java:263) at com.sun.enterprise.web.connector.grizzly.DefaultReadTask.doTask(DefaultReadTask.java:214) at com.sun.enterprise.web.portunif.PortUnificationPipeline$PUTask.doTask(PortUnificationPipeline.java:380) at com.sun.enterprise.web.connector.grizzly.TaskBase.run(TaskBase.java:265) at com.sun.enterprise.web.connector.grizzly.ssl.SSLWorkerThread.run(SSLWorkerThread.java:106) Caused by: javax.xml.ws.WebServiceException: java.lang.NullPointerException at com.sun.enterprise.security.jmac.config.PipeHelper.makeFaultResponse(PipeHelper.java:328) at com.sun.enterprise.security.jmac.config.PipeHelper.getFaultResponse(PipeHelper.java:366) at com.sun.enterprise.webservice.CommonServerSecurityPipe.processRequest(CommonServerSecurityPipe.java:227) at com.sun.enterprise.webservice.CommonServerSecurityPipe.process(CommonServerSecurityPipe.java:133) at com.sun.xml.ws.api.pipe.helper.PipeAdapter.processRequest(PipeAdapter.java:115) at com.sun.xml.ws.api.pipe.Fiber._doRun(Fiber.java:595) at com.sun.xml.ws.api.pipe.Fiber._doRun(Fiber.java:554) at com.sun.xml.ws.api.pipe.Fiber.doRun(Fiber.java:539) at com.sun.xml.ws.api.pipe.Fiber.runSync(Fiber.java:436) at com.sun.xml.ws.server.WSEndpointImpl$2.process(WSEndpointImpl.java:243) at com.sun.xml.ws.transport.http.HttpAdapter$HttpToolkit.handle(HttpAdapter.java:444) at com.sun.xml.ws.transport.http.HttpAdapter.handle(HttpAdapter.java:244) at com.sun.xml.ws.transport.http.servlet.ServletAdapter.handle(ServletAdapter.java:135) at com.sun.enterprise.webservice.Ejb3MessageDispatcher.handlePost(Ejb3MessageDispatcher.java:113) at com.sun.enterprise.webservice.Ejb3MessageDispatcher.invoke(Ejb3MessageDispatcher.java:87) at com.sun.enterprise.webservice.EjbWebServiceServlet.dispatchToEjbEndpoint(EjbWebServiceServlet.java:228) at com.sun.enterprise.webservice.EjbWebServiceServlet.service(EjbWebServiceServlet.java:157) at javax.servlet.http.HttpServlet.service(HttpServlet.java:847) at com.sun.enterprise.web.AdHocContextValve.invoke(AdHocContextValve.java:114) at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:648) at org.apache.catalina.