An exception when deleting objects

Hi everyone,

In some cases of deleting objects, we've got exception which is very difficult to know the reason.

Message: An exception occurred while serializing feedback

Track log:

org.codehaus.jackson.JsonGenerationException: Can not write a field name, expecting a value
	at org.codehaus.jackson.impl.JsonGeneratorBase._reportError(JsonGeneratorBase.java:480)
	at org.codehaus.jackson.impl.WriterBasedGenerator.writeFieldName(WriterBasedGenerator.java:195)
	at com.mendix.webui.jsonserialization.JsonGeneratorWrapper$$anonfun$writeFieldName$1.apply(JsonGeneratorWrapper.scala:43)
	at com.mendix.webui.jsonserialization.JsonGeneratorWrapper$$anonfun$writeFieldName$1.apply(JsonGeneratorWrapper.scala:43)
	at scala.collection.immutable.List.foreach(List.scala:381)
	at scala.collection.generic.TraversableForwarder$class.foreach(TraversableForwarder.scala:35)
	at scala.collection.mutable.ListBuffer.foreach(ListBuffer.scala:45)
	at com.mendix.webui.jsonserialization.JsonGeneratorWrapper.writeFieldName(JsonGeneratorWrapper.scala:43)
	at com.mendix.webui.jsonserialization.FeedbackSerializer$.serializeFeedback(FeedbackSerializer.scala:17)
	at com.mendix.webui.jsonserialization.ResultSerializer.serializeFeedback(ResultSerializer.scala:50)
	at com.mendix.webui.requesthandling.FeedbackHandling$class.processFeedback(FeedbackHandling.scala:54)
	at com.mendix.webui.requesthandling.ClientRequestHandler.processFeedback(ClientRequestHandler.scala:34)
	at com.mendix.webui.requesthandling.ClientRequestHandler$$anonfun$handleRequest$1.apply$mcV$sp(ClientRequestHandler.scala:352)
	at com.mendix.webui.requesthandling.ClientRequestHandler$$anonfun$handleRequest$1.apply(ClientRequestHandler.scala:293)
	at com.mendix.webui.requesthandling.ClientRequestHandler$$anonfun$handleRequest$1.apply(ClientRequestHandler.scala:293)
	at com.mendix.basis.actionmanagement.IMonitoredAction$$anon$1.execute(IMonitoredAction.scala:47)
	at com.mendix.util.classloading.Runner.doRunUsingClassLoaderOf(Runner.java:33)
	at com.mendix.basis.actionmanagement.IMonitoredAction$class.monitor(IMonitoredAction.scala:49)
	at com.mendix.webui.requesthandling.ClientRequestHandler$ClientMonitoredAction.monitor(ClientRequestHandler.scala:410)
	at com.mendix.webui.requesthandling.ClientRequestHandler.handleRequest(ClientRequestHandler.scala:293)
	at com.mendix.webui.requesthandling.ClientRequestHandler.handleActionWithSessionRequired(ClientRequestHandler.scala:235)
	at com.mendix.webui.requesthandling.ClientRequestHandler.handleAction(ClientRequestHandler.scala:202)
	at com.mendix.webui.requesthandling.ClientRequestHandler.liftedTree1$1(ClientRequestHandler.scala:101)
	at com.mendix.webui.requesthandling.ClientRequestHandler.processRequest(ClientRequestHandler.scala:93)
	at com.mendix.externalinterface.connector.RequestHandler.doProcessRequest(RequestHandler.java:40)
	at com.mendix.external.connector.MxRuntimeConnector$1.execute(MxRuntimeConnector.java:70)
	at com.mendix.external.connector.MxRuntimeConnector$1.execute(MxRuntimeConnector.java:67)
	at com.mendix.util.classloading.Runner.doRunUsingClassLoaderOf(Runner.java:33)
	at com.mendix.external.connector.MxRuntimeConnector.processRequest(MxRuntimeConnector.java:73)
	at com.mendix.basis.impl.MxRuntimeImpl.processRequest(MxRuntimeImpl.java:885)
	at com.mendix.m2ee.appcontainer.server.handler.RuntimeHandler.handle(RuntimeHandler.java:41)
	at org.eclipse.jetty.server.handler.HandlerList.handle(HandlerList.java:52)
	at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:116)
	at org.eclipse.jetty.server.Server.handle(Server.java:368)
	at org.eclipse.jetty.server.AbstractHttpConnection.handleRequest(AbstractHttpConnection.java:489)
	at org.eclipse.jetty.server.AbstractHttpConnection.content(AbstractHttpConnection.java:953)
	at org.eclipse.jetty.server.AbstractHttpConnection$RequestHandler.content(AbstractHttpConnection.java:1014)
	at org.eclipse.jetty.http.HttpParser.parseNext(HttpParser.java:861)
	at org.eclipse.jetty.http.HttpParser.parseAvailable(HttpParser.java:240)
	at org.eclipse.jetty.server.AsyncHttpConnection.handle(AsyncHttpConnection.java:82)
	at org.eclipse.jetty.io.nio.SelectChannelEndPoint.handle(SelectChannelEndPoint.java:628)
	at org.eclipse.jetty.io.nio.SelectChannelEndPoint$1.run(SelectChannelEndPoint.java:52)
	at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:608)
	at org.eclipse.jetty.util.thread.QueuedThreadPool$3.run(QueuedThreadPool.java:543)
	at java.lang.Thread.run(Thread.java:745)

and 

com.mendix.systemwideinterfaces.MendixRuntimeException: Object access cannot be retrieved.
	at com.mendix.basis.objectmanagement.SchemeManagerImpl.retrieveAndSetObjectAccess(SchemeManagerImpl.java:1073)

Caused by: java.lang.IndexOutOfBoundsException: Index: 0, Size: 0
	at java.util.ArrayList.rangeCheck(ArrayList.java:653)
	at java.util.ArrayList.get(ArrayList.java:429)
	at com.mendix.connectionbus.data.InternalDataTable.get(InternalDataTable.java:200)
	at com.mendix.connectionbus.data.InternalDataTable$1.get(InternalDataTable.java:253)
	at com.mendix.connectionbus.data.InternalDataTable$1.get(InternalDataTable.java:211)
	at com.mendix.basis.objectmanagement.SchemeManagerImpl.retrieveAndSetObjectAccess(SchemeManagerImpl.java:1070)
	at com.mendix.basis.objectmanagement.MendixObjectMemberImpl.checkAccessRetrieved(MendixObjectMemberImpl.java:165)
	at com.mendix.basis.objectmanagement.MendixObjectMemberImpl.hasReadAccess(MendixObjectMemberImpl.java:174)
	at com.mendix.basis.objectmanagement.MendixObjectImpl.getMembers(MendixObjectImpl.java:88)
	at com.mendix.webui.requesthandling.HashUtil$.calculateHash(HashUtil.scala:27)
	at com.mendix.webui.jsonserialization.ResultSerializer.com$mendix$webui$jsonserialization$ResultSerializer$$generateMendixObject(ResultSerializer.scala:138)

Have you have the same problem? And do you know how to fix it?

Best regards,