java.lang.NullPointerException when running fast client

Hello!
  My UIMA AS client is using UimaAsynchronousEngine for sending messages to
a UIMA pipeline. If the process of sending is fast (with 100 ms delay or
without any delay) the attached exception(java.lang.NullPointerException)
is thrown. Please advice. Thank you.
  Regards,
 Florin

My code is:

//constructor
Client() {
   cas = CasCreationUtils.createCas(uimaTypeDescriptors);
}

//main method
main() {
  Client client = new Client();
 for (int i = 0; i < 100000; i++) {
            System.out.println("Sending message #"+i);
            client.sendToUIMA("Test message:"+i);
            Thread.sleep(100);
   }
}

 public void sendToUIMA(String msg) throws Exception {
        JCas jcas = cas.getJCas();
        jcas.reset();
        jcas.setDocumentText(msg);
        uimaEEEngine.sendCAS(jcas.getCas());

    }

org.apache.uima.adapter.jms.client.BaseUIMAAsynchronousEngineCommon_impl$2
onMessage
WARNING:
java.lang.NullPointerException
    at
org.apache.uima.cas.impl.XmiCasDeserializer$XmiCasDeserializerHandler.handleFeature(XmiCasDeserializer.java:769)
    at
org.apache.uima.cas.impl.XmiCasDeserializer$XmiCasDeserializerHandler.readFS(XmiCasDeserializer.java:734)
    at
org.apache.uima.cas.impl.XmiCasDeserializer$XmiCasDeserializerHandler.readFS(XmiCasDeserializer.java:509)
    at
org.apache.uima.cas.impl.XmiCasDeserializer$XmiCasDeserializerHandler.startElement(XmiCasDeserializer.java:391)
    at org.apache.xerces.parsers.AbstractSAXParser.startElement(Unknown
Source)
    at
org.apache.xerces.parsers.AbstractXMLDocumentParser.emptyElement(Unknown
Source)
    at
org.apache.xerces.impl.XMLNSDocumentScannerImpl.scanStartElement(Unknown
Source)
    at
org.apache.xerces.impl.XMLDocumentFragmentScannerImpl$FragmentContentDispatcher.dispatch(Unknown
Source)
    at
org.apache.xerces.impl.XMLDocumentFragmentScannerImpl.scanDocument(Unknown
Source)
    at org.apache.xerces.parsers.XML11Configuration.parse(Unknown Source)
    at org.apache.xerces.parsers.XML11Configuration.parse(Unknown Source)
    at org.apache.xerces.parsers.XMLParser.parse(Unknown Source)
    at org.apache.xerces.parsers.AbstractSAXParser.parse(Unknown Source)
    at
org.apache.uima.aae.UimaSerializer.deserializeCasFromXmi(UimaSerializer.java:191)
    at
org.apache.uima.adapter.jms.client.BaseUIMAAsynchronousEngineCommon_impl.deserialize(BaseUIMAAsynchronousEngineCommon_impl.java:1613)
    at
org.apache.uima.adapter.jms.client.BaseUIMAAsynchronousEngineCommon_impl.deserializeCAS(BaseUIMAAsynchronousEngineCommon_impl.java:1646)
    at
org.apache.uima.adapter.jms.client.BaseUIMAAsynchronousEngineCommon_impl.deserializeAndCompleteProcessingReply(BaseUIMAAsynchronousEngineCommon_impl.java:1883)
    at
org.apache.uima.adapter.jms.client.BaseUIMAAsynchronousEngineCommon_impl.handleProcessReply(BaseUIMAAsynchronousEngineCommon_impl.java:1208)
    at
org.apache.uima.adapter.jms.client.BaseUIMAAsynchronousEngineCommon_impl$2.run(BaseUIMAAsynchronousEngineCommon_impl.java:1714)
    at
java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1110)
    at
java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:603)
    at java.lang.Thread.run(Thread.java:722)