Playground is stuck when namespace option is missing

[TobiasNx]

When trying to handle-marcxml without configuring the namespace but that has no namespace the playground stucks in an endless procession window.

When trying to run this code on the CLI, the process breaks:

$ '/home/tobias/Downloads/metafix-runner-1.1.2/bin/metafix-runner' '/home/tobias/Downloads/Unbenannter Ordner/playground.flux' 
Exception in thread "main" java.lang.AssertionError: unknown or unexpected state: IN_STREAM
	at org.metafacture.biblio.marc21.Marc21Encoder.literal(Marc21Encoder.java:195)
	at org.metafacture.biblio.marc21.MarcXmlHandler.endElement(MarcXmlHandler.java:135)
	at java.xml/com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.endElement(AbstractSAXParser.java:618)
	at java.xml/com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanEndElement(XMLDocumentFragmentScannerImpl.java:1728)
	at java.xml/com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl$FragmentContentDriver.next(XMLDocumentFragmentScannerImpl.java:2899)
	at java.xml/com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl.next(XMLDocumentScannerImpl.java:605)
	at java.xml/com.sun.org.apache.xerces.internal.impl.XMLNSDocumentScannerImpl.next(XMLNSDocumentScannerImpl.java:112)
	at java.xml/com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanDocument(XMLDocumentFragmentScannerImpl.java:542)
	at java.xml/com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:889)
	at java.xml/com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:825)
	at java.xml/com.sun.org.apache.xerces.internal.parsers.XMLParser.parse(XMLParser.java:141)
	at java.xml/com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.parse(AbstractSAXParser.java:1224)
	at java.xml/com.sun.org.apache.xerces.internal.jaxp.SAXParserImpl$JAXPSAXParser.parse(SAXParserImpl.java:637)
	at org.metafacture.xml.XmlDecoder.process(XmlDecoder.java:73)
	at org.metafacture.xml.XmlDecoder.process(XmlDecoder.java:44)
	at org.metafacture.io.FileOpener.process(FileOpener.java:158)
	at org.metafacture.io.FileOpener.process(FileOpener.java:41)
	at org.metafacture.flux.parser.StringSender.process(StringSender.java:43)
	at org.metafacture.flux.parser.Flow.start(Flow.java:118)
	at org.metafacture.flux.parser.FluxProgramm.start(FluxProgramm.java:168)
	at org.metafacture.runner.Flux.main(Flux.java:87)

It seems that something is not correct here.

This issue was reported by hbz Verbundgruppe in context of metafacture/metafacture-core#569 and by @dr0i in context of metafacture/metafacture-core#567