NullPointerException on EPUB containing SVG image with DublinCore metadata(?)

[kingjon3377]

I'm getting a NullPointerException when I try to run EpubCheck 5.0.1 on my EPUBs. I've managed to prepare a reasonably minimal example (attached, renamed to .ZIP: minimal.zip; constructed from this minimal EPUB project (with its errors fixed up) and then this public-domain SVG image embedded). The command-line output, including the stacktrace, is as follows:

Validating using EPUB version 3.3 rules.
java.lang.NullPointerException: Cannot invoke "java.util.Map.put(Object, Object)" because "this.mediaSources" is null
	at com.adobe.epubcheck.ops.OPSHandler30.startMediaSource(OPSHandler30.java:614)
	at com.adobe.epubcheck.ops.OPSHandler30.startElement(OPSHandler30.java:421)
	at com.adobe.epubcheck.xml.handlers.XMLHandler.startElement(XMLHandler.java:115)
	at com.adobe.epubcheck.xml.handlers.DelegateDefaultHandler.startElement(DelegateDefaultHandler.java:170)
	at com.adobe.epubcheck.xml.handlers.WrappingDefaultHandler.startElement(WrappingDefaultHandler.java:95)
	at com.adobe.epubcheck.xml.handlers.PreprocessingDefaultHandler.startElement(PreprocessingDefaultHandler.java:59)
	at org.apache.xerces.parsers.AbstractSAXParser.startElement(Unknown Source)
	at org.apache.xerces.impl.XMLNSDocumentScannerImpl.scanStartElement(Unknown Source)
	at org.apache.xerces.impl.XMLDocumentFragmentScannerImpl$FragmentContentDispatcher.dispatch(Unknown Source)
	at org.apache.xerces.impl.XMLDocumentFragmentScannerImpl.scanDocument(Unknown Source)
	at org.apache.xerces.parsers.XML11Configuration.parse(Unknown Source)
	at org.apache.xerces.parsers.XML11Configuration.parse(Unknown Source)
	at org.apache.xerces.parsers.XMLParser.parse(Unknown Source)
	at org.apache.xerces.parsers.AbstractSAXParser.parse(Unknown Source)
	at org.apache.xerces.jaxp.SAXParserImpl$JAXPSAXParser.parse(Unknown Source)
	at org.apache.xerces.jaxp.SAXParserImpl.parse(Unknown Source)
	at com.adobe.epubcheck.xml.XMLParser.process(XMLParser.java:176)
	at com.adobe.epubcheck.ops.OPSChecker.validate(OPSChecker.java:127)
	at com.adobe.epubcheck.ops.OPSChecker.checkContent(OPSChecker.java:97)
	at com.adobe.epubcheck.opf.PublicationResourceChecker.check(PublicationResourceChecker.java:45)
	at com.adobe.epubcheck.opf.OPFChecker.checkItemContent(OPFChecker.java:398)
	at com.adobe.epubcheck.opf.OPFChecker.checkPackage(OPFChecker.java:136)
	at com.adobe.epubcheck.opf.OPFChecker30.checkPackage(OPFChecker30.java:67)
	at com.adobe.epubcheck.opf.OPFChecker.check(OPFChecker.java:94)
	at com.adobe.epubcheck.ocf.OCFChecker.check(OCFChecker.java:173)
	at com.adobe.epubcheck.api.EpubCheck.doValidate(EpubCheck.java:218)
	at com.adobe.epubcheck.tool.EpubChecker.validateFile(EpubChecker.java:245)
	at com.adobe.epubcheck.tool.EpubChecker.processFile(EpubChecker.java:320)
	at com.adobe.epubcheck.tool.EpubChecker.run(EpubChecker.java:145)
	at com.adobe.epubcheck.tool.Checker.main(Checker.java:31)
Messages: 0 fatals / 0 errors / 0 warnings / 0 infos

EPUBCheck completed

[shiestyle]

We found a similar case when navigation document has an incorrect link.

<nav epub:type="toc" id="toc">
<h1>Navigation</h1>
<ol>
<li><a href="xhtml/p-cover.xhtml">cover</a></li>
<li><a href="xhtml/p-001.xhtml#xxx">p-001</a></li>
</ol>
</nav>

If p-001.xhtml doesn't have an anchor #xxx, NullPointerException will be occurred.

[rdeltour]

Definitely looks like a bug. Thanks for the report @kingjon3377!

@shiestyle yours seem to be a different case, would you mind opening a separate issue?