Open Source Probe: WSO2 DSS Error Nesting problem | Error while writing to the output stream using JsonWriter

I had several resources and out of all, one gave an error as follows when called via a jaggery application.

TID: [-1234] [] [2017-08-18 06:39:17,622] ERROR {org.wso2.carbon.dataservices.core.description.query.SQLQuery} - Nesting problem. {org.wso2.carbon.dataservices.core.description.query.SQLQuery}

java.lang.IllegalStateException: Nesting problem.

at com.google.gson.stream.JsonWriter.beforeValue(JsonWriter.java:631)

at com.google.gson.stream.JsonWriter.open(JsonWriter.java:325)

at com.google.gson.stream.JsonWriter.beginObject(JsonWriter.java:308)

at org.apache.axis2.json.gson.GsonXMLStreamWriter.writeStartElement(GsonXMLStreamWriter.java:319)

at org.wso2.carbon.dataservices.core.engine.XMLWriterHelper.writeResultElement(XMLWriterHelper.java:144)

at org.wso2.carbon.dataservices.core.engine.StaticOutputElement.executeElement(StaticOutputElement.java:251)

at org.wso2.carbon.dataservices.core.engine.OutputElement.execute(OutputElement.java:89)

at org.wso2.carbon.dataservices.core.engine.OutputElementGroup.executeElement(OutputElementGroup.java:106)

at org.wso2.carbon.dataservices.core.engine.OutputElement.execute(OutputElement.java:89)

at org.wso2.carbon.dataservices.core.description.query.Query.writeResultEntry(Query.java:440)

at org.wso2.carbon.dataservices.core.description.query.SQLQuery.processPostNormalQuery(SQLQuery.java:823)

at org.wso2.carbon.dataservices.core.description.query.SQLQuery.runPostQuery(SQLQuery.java:2197)

at org.wso2.carbon.dataservices.core.description.query.Query.execute(Query.java:307)

at org.wso2.carbon.dataservices.core.engine.CallQuery.executeElement(CallQuery.java:286)

at org.wso2.carbon.dataservices.core.engine.OutputElement.execute(OutputElement.java:89)

at org.wso2.carbon.dataservices.core.description.resource.Resource.execute(Resource.java:67)

at org.wso2.carbon.dataservices.core.engine.DataService.invoke(DataService.java:585)

at org.wso2.carbon.dataservices.core.engine.DSOMDataSource.execute(DSOMDataSource.java:96)

at org.wso2.carbon.dataservices.core.engine.DSOMDataSource.serialize(DSOMDataSource.java:107)

at org.apache.axiom.om.impl.llom.OMSourcedElementImpl.internalSerialize(OMSourcedElementImpl.java:691)

at org.apache.axiom.om.impl.llom.OMSourcedElementImpl.serializeAndConsume(OMSourcedElementImpl.java:754)

at org.apache.axis2.json.gson.JsonFormatter.writeTo(JsonFormatter.java:100)

at org.apache.axis2.transport.http.CommonsHTTPTransportSender.sendUsingOutputStream(CommonsHTTPTransportSender.java:411)

at org.apache.axis2.transport.http.CommonsHTTPTransportSender.invoke(CommonsHTTPTransportSender.java:288)

at org.apache.axis2.engine.AxisEngine.send(AxisEngine.java:442)

at org.apache.axis2.receivers.AbstractInOutSyncMessageReceiver.invokeBusinessLogic(AbstractInOutSyncMessageReceiver.java:45)

at org.apache.axis2.receivers.AbstractMessageReceiver.receive(AbstractMessageReceiver.java:110)

at org.apache.axis2.engine.AxisEngine.receive(AxisEngine.java:180)

at org.apache.axis2.transport.http.util.RESTUtil.invokeAxisEngine(RESTUtil.java:144)

at org.apache.axis2.transport.http.util.RESTUtil.processURLRequest(RESTUtil.java:139)

at org.apache.axis2.transport.http.AxisServlet$RestRequestProcessor.processURLRequest(AxisServlet.java:843)

at org.wso2.carbon.core.transports.CarbonServlet.handleRestRequest(CarbonServlet.java:303)

at org.wso2.carbon.core.transports.CarbonServlet.doGet(CarbonServlet.java:152)

at javax.servlet.http.HttpServlet.service(HttpServlet.java:620)

at javax.servlet.http.HttpServlet.service(HttpServlet.java:727)

at org.eclipse.equinox.http.servlet.internal.ServletRegistration.service(ServletRegistration.java:61)

at org.eclipse.equinox.http.servlet.internal.ProxyServlet.processAlias(ProxyServlet.java:128)

at org.eclipse.equinox.http.servlet.internal.ProxyServlet.service(ProxyServlet.java:68)

at javax.servlet.http.HttpServlet.service(HttpServlet.java:727)

at org.wso2.carbon.tomcat.ext.servlet.DelegationServlet.service(DelegationServlet.java:68)

at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303)

at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)

at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)

at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)

at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)

at org.wso2.carbon.ui.filters.CSRFPreventionFilter.doFilter(CSRFPreventionFilter.java:88)

at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)

at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)

at org.wso2.carbon.ui.filters.CRLFPreventionFilter.doFilter(CRLFPreventionFilter.java:59)

at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)

at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)

at org.wso2.carbon.tomcat.ext.filter.CharacterSetFilter.doFilter(CharacterSetFilter.java:61)

at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)

at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)

at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:220)

at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:122)

at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:504)

at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:170)

at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)

at org.wso2.carbon.tomcat.ext.valves.CompositeValve.continueInvocation(CompositeValve.java:99)

at org.wso2.carbon.tomcat.ext.valves.CarbonTomcatValve$1.invoke(CarbonTomcatValve.java:47)

at org.wso2.carbon.webapp.mgt.TenantLazyLoaderValve.invoke(TenantLazyLoaderValve.java:57)

at org.wso2.carbon.tomcat.ext.valves.TomcatValveContainer.invokeValves(TomcatValveContainer.java:47)

at org.wso2.carbon.tomcat.ext.valves.CompositeValve.invoke(CompositeValve.java:62)

at org.wso2.carbon.tomcat.ext.valves.CarbonStuckThreadDetectionValve.invoke(CarbonStuckThreadDetectionValve.java:159)

at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:950)

at org.wso2.carbon.tomcat.ext.valves.CarbonContextCreatorValve.invoke(CarbonContextCreatorValve.java:57)

at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)

at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:421)

at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1074)

at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:611)

at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1739)

at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1698)

at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)

at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)

at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)

at java.lang.Thread.run(Thread.java:745)

TID: [-1234] [] [2017-08-18 06:39:17,624] ERROR {org.wso2.carbon.dataservices.core.engine.DataService} - DS Fault Message: Error in 'SQLQuery.processPostNormalQuery': Nesting problem._DS Code: DATABASE_ERROR_Source Data Service:-_Name: EngineeringAppDashboard_Location: /EngineeringAppDashboard.dbs_Description: N/A_Default Namespace: http://ws.wso2.org/dataservice_Current Request Name: _get_alldepartmentsinallocations_Current Params: {}_Nested Exception:-_java.lang.IllegalStateException: Nesting problem._ (Sanitized) {org.wso2.carbon.dataservices.core.engine.DataService}

DS Fault Message: Error in 'SQLQuery.processPostNormalQuery': Nesting problem.

DS Code: DATABASE_ERROR

Source Data Service:-

Name: EngineeringAppDashboard

Location: /EngineeringAppDashboard.dbs

Description: N/A

Default Namespace: http://ws.wso2.org/dataservice

Current Request Name: _get_alldepartmentsinallocations

Current Params: {}

Nested Exception:-

java.lang.IllegalStateException: Nesting problem.

at org.wso2.carbon.dataservices.core.description.query.SQLQuery.processPostNormalQuery(SQLQuery.java:829)