org.apache.cxf.interceptor.Fault: Unmarshalling Error: Illegal character (NULL, unicode 0) encountered: not valid in any content

Question

I am using a cxf webservice which uses local transport and accessing the webservice from java application. Webservice is reading a file and sending through webservice call. I am using the byte size as 512. Suppose the file size is 1200. First two attempt of retrieving the file is success and for the last chunk i am getting org.apache.cxf.interceptor.Fault: Unmarshalling Error: Illegal character (NULL, unicode 0) encountered: not valid in any content.

Here chunk represents 512 bytes. I am converting bytes to string and returning from web service.In the last chunk only 16 byte value is filled and remaining are filled with zeros. Any help will be appreciated. I am using cxf webservice 2.7.5, jdk1.7 ,Redhat Linux.

Stack trace:

org.apache.cxf.interceptor.Fault: Unmarshalling Error: Illegal character (NULL, unicode 0) encountered: not valid in any content
 at [row,col {unknown-source}]: [2,1]
        at org.apache.cxf.jaxb.JAXBEncoderDecoder.unmarshall(JAXBEncoderDecoder.java:808)
        at org.apache.cxf.jaxb.JAXBEncoderDecoder.unmarshall(JAXBEncoderDecoder.java:629)
        at org.apache.cxf.jaxb.io.DataReaderImpl.read(DataReaderImpl.java:157)
        at org.apache.cxf.interceptor.DocLiteralInInterceptor.handleMessage(DocLiteralInInterceptor.java:103)
        at org.apache.cxf.phase.PhaseInterceptorChain.doIntercept(PhaseInterceptorChain.java:271)
        at org.apache.cxf.endpoint.ClientImpl.onMessage(ClientImpl.java:800)
        at org.apache.cxf.transport.http.HTTPConduit$WrappedOutputStream.handleResponseInternal(HTTPConduit.java:1592)
        at org.apache.cxf.transport.http.HTTPConduit$WrappedOutputStream.handleResponse(HTTPConduit.java:1490)
        at org.apache.cxf.transport.http.HTTPConduit$WrappedOutputStream.close(HTTPConduit.java:1309)
        at org.apache.cxf.transport.AbstractConduit.close(AbstractConduit.java:56)
        at org.apache.cxf.transport.http.HTTPConduit.close(HTTPConduit.java:622)
        at org.apache.cxf.interceptor.MessageSenderInterceptor$MessageSenderEndingInterceptor.handleMessage(MessageSenderInterceptor.java:62)
        at org.apache.cxf.phase.PhaseInterceptorChain.doIntercept(PhaseInterceptorChain.java:271)
        at org.apache.cxf.endpoint.ClientImpl.doInvoke(ClientImpl.java:530)
        at org.apache.cxf.endpoint.ClientImpl.invoke(ClientImpl.java:463)
        at org.apache.cxf.endpoint.ClientImpl.invoke(ClientImpl.java:366)
        at org.apache.cxf.endpoint.ClientImpl.invoke(ClientImpl.java:319)
        at org.apache.cxf.frontend.ClientProxy.invokeSync(ClientProxy.java:96)
        at org.apache.cxf.jaxws.JaxWsClientProxy.invoke(JaxWsClientProxy.java:133)
        at $Proxy62.getJobLog(Unknown Source)
        at com.java.process.AClass.getMessage(AClass.java:468)
        at com.java.process.AClass.getXXXX(AClass.java:156)
        at com.java.process.AClass.main(CLIClientStartup.java:409)
Caused by: javax.xml.bind.UnmarshalException
 - with linked exception:
[com.ctc.wstx.exc.WstxUnexpectedCharException: Illegal character (NULL, unicode 0) encountered: not valid in any content
 at [row,col {unknown-source}]: [2,1]]
        at com.sun.xml.bind.v2.runtime.unmarshaller.UnmarshallerImpl.handleStreamException(UnmarshallerImpl.java:436)
        at com.sun.xml.bind.v2.runtime.unmarshaller.UnmarshallerImpl.unmarshal0(UnmarshallerImpl.java:372)
        at com.sun.xml.bind.v2.runtime.unmarshaller.UnmarshallerImpl.unmarshal(UnmarshallerImpl.java:349)
        at org.apache.cxf.jaxb.JAXBEncoderDecoder.doUnmarshal(JAXBEncoderDecoder.java:769)
        at org.apache.cxf.jaxb.JAXBEncoderDecoder.access$100(JAXBEncoderDecoder.java:94)
        at org.apache.cxf.jaxb.JAXBEncoderDecoder$1.run(JAXBEncoderDecoder.java:797)
        at java.security.AccessController.doPrivileged(Native Method)
        at org.apache.cxf.jaxb.JAXBEncoderDecoder.unmarshall(JAXBEncoderDecoder.java:795)
        ... 23 more
Caused by: com.ctc.wstx.exc.WstxUnexpectedCharException: Illegal character (NULL, unicode 0) encountered: not valid in any content
 at [row,col {unknown-source}]: [2,1]
        at com.ctc.wstx.sr.StreamScanner.constructNullCharException(StreamScanner.java:630)
        at com.ctc.wstx.sr.StreamScanner.throwInvalidSpace(StreamScanner.java:660)
        at com.ctc.wstx.sr.BasicStreamReader.readTextPrimary(BasicStreamReader.java:4576)
        at com.ctc.wstx.sr.BasicStreamReader.nextFromTree(BasicStreamReader.java:2879)
        at com.ctc.wstx.sr.BasicStreamReader.next(BasicStreamReader.java:1072)
        at com.sun.xml.bind.v2.runtime.unmarshaller.StAXStreamConnector.bridge(StAXStreamConnector.java:196)
        at com.sun.xml.bind.v2.runtime.unmarshaller.UnmarshallerImpl.unmarshal0(UnmarshallerImpl.java:370)
        ... 29 more

Solution

From here

The problem that causes these XmlExceptions is that the data being read or loaded contains characters that are illegal according to the XML specifications. Almost always, these characters are in the ASCII control character range (think whacky characters like null, bell, backspace, etc). These aren’t characters that have any business being in XML data; they’re illegal characters that should be removed, usually having found their way into the data from file format conversions, like when someone tries to create an XML file from Excel data, or export their data to XML from a format that may be stored as binary.

And an example for sanitizing the data before unmarshal. Error about invalid XML characters on Java

Maybe you should use something out of the box for transferring files, like MTOM check here

Or you could use CDATA syntax to wrap the content, so the part that evaluates to null will be received as literal.