NullPointerException when running an XSLT Camel route with Debug logging

Issue

• The following exception occurs when running a XSLT Camel route with debug logging enabled:

JBossFuse:karaf@root> log:set debug
JBossFuse:karaf@root> Warning:  The encoding 'UTF-8' is not supported by the Java runtime.
Warning: encoding "UTF-8" not supported, using UTF-8
java.lang.NullPointerException
    at net.sf.saxon.tree.tiny.TinyBuilder.startElement(TinyBuilder.java:236)
    at net.sf.saxon.event.ReceivingContentHandler.startElement(ReceivingContentHandler.java:285)
    at org.apache.xalan.xsltc.trax.DOM2SAX.parse(DOM2SAX.java:285)
    at org.apache.xalan.xsltc.trax.DOM2SAX.parse(DOM2SAX.java:149)
    at net.sf.saxon.event.Sender.sendSAXSource(Sender.java:405)
    at net.sf.saxon.event.Sender.send(Sender.java:152)
    at net.sf.saxon.Controller.transform(Controller.java:1790)
    at org.apache.camel.builder.xml.XsltBuilder.process(XsltBuilder.java:128)
    at org.apache.camel.impl.ProcessorEndpoint.onExchange(ProcessorEndpoint.java:101)
    at org.apache.camel.component.xslt.XsltEndpoint.onExchange(XsltEndpoint.java:81)
    at org.apache.camel.impl.ProcessorEndpoint$1.process(ProcessorEndpoint.java:71)
    at org.apache.camel.util.AsyncProcessorConverterHelper$ProcessorToAsyncProcessorBridge.process(AsyncProcessorConverterHelper.java:61)
    at org.apache.camel.util.AsyncProcessorHelper.process(AsyncProcessorHelper.java:73)
    at org.apache.camel.processor.SendProcessor$2.doInAsyncProducer(SendProcessor.java:122)
    at org.apache.camel.impl.ProducerCache.doInAsyncProducer(ProducerCache.java:298)
    at org.apache.camel.processor.SendProcessor.process(SendProcessor.java:117)
    at org.apache.camel.util.AsyncProcessorHelper.process(AsyncProcessorHelper.java:73)
    at org.apache.camel.processor.DelegateAsyncProcessor.processNext(DelegateAsyncProcessor.java:99)
        ...

Route:

<camel:camelContext>
        <camel:route>
            <camel:from uri="cxf:bean:cxfEndpoint" />
                        <camel:convertBodyTo type="java.lang.String" />
                        <camel:to uri="log:RequestLog" />
                        <camel:to uri="xslt:xslt/transform.xsl?transformerFactory=saxonTransformerFactory" />
        </camel:route>
</camel:camelContext>