Why do I get java.lang.NullPointerException only for a specific file ?

Hi,

I've a 74MB xml document and I've split it into 2 docs:52MB and 22MB respectively.

I'm parsing the file using common Digester library, and everything works perfectly for the small file, but I get a NullPointerExceptio with the big one.

I don't think the issue is the code because it works for the small file... I guess the problem is with the file itself.

I've parsed the files with the same parser, so I don't think the files have issues either.

In conclusion I dunno where the issue is. This is the code: #1726063 - Pastie

And these are the files:
http://dl.dropbox.com/u/72686/test.xml
http://dl.dropbox.com/u/72686/train.xml

thanks

This is the exception
SEVERE: End event threw exception
java.lang.reflect.InvocationTargetException
at sun.reflect.GeneratedMethodAccessor7.invoke(Unknow n Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(De legatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.apache.commons.beanutils.MethodUtils.invokeMet hod(MethodUtils.java:216)
at org.apache.commons.digester.SetNextRule.end(SetNex tRule.java:220)
at org.apache.commons.digester.Rule.end(Rule.java:257 )
at org.apache.commons.digester.Digester.endElement(Di gester.java:1345)
at com.sun.org.apache.xerces.internal.parsers.Abstrac tSAXParser.endElement(AbstractSAXParser.java:601)
at com.sun.org.apache.xerces.internal.impl.XMLDocumen tFragmentScannerImpl.scanEndElement(XMLDocumentFra gmentScannerImpl.java:1782)
at com.sun.org.apache.xerces.internal.impl.XMLDocumen tFragmentScannerImpl$FragmentContentDriver.next(XM LDocumentFragmentScannerImpl.java:2938)
at com.sun.org.apache.xerces.internal.impl.XMLDocumen tScannerImpl.next(XMLDocumentScannerImpl.java:648)
at com.sun.org.apache.xerces.internal.impl.XMLDocumen tFragmentScannerImpl.scanDocument(XMLDocumentFragm entScannerImpl.java:511)
at com.sun.org.apache.xerces.internal.parsers.XML11Co nfiguration.parse(XML11Configuration.java:808)
at com.sun.org.apache.xerces.internal.parsers.XML11Co nfiguration.parse(XML11Configuration.java:737)
at com.sun.org.apache.xerces.internal.parsers.XMLPars er.parse(XMLParser.java:119)
at com.sun.org.apache.xerces.internal.parsers.Abstrac tSAXParser.parse(AbstractSAXParser.java:1205)
at com.sun.org.apache.xerces.internal.jaxp.SAXParserI mpl$JAXPSAXParser.parse(SAXParserImpl.java:522)
at org.apache.commons.digester.Digester.parse(Digeste r.java:1871)
at CentroidGenerator.main(CentroidGenerator.java:137)
Caused by: java.lang.NullPointerException
at CentroidGenerator.nextItem(CentroidGenerator.java: 62)
... 19 more
Exception in thread "main" java.lang.NullPointerException
at org.apache.commons.digester.Digester.createSAXExce ption(Digester.java:3363)
at org.apache.commons.digester.Digester.createSAXExce ption(Digester.java:3389)
at org.apache.commons.digester.Digester.endElement(Di gester.java:1348)
at com.sun.org.apache.xerces.internal.parsers.Abstrac tSAXParser.endElement(AbstractSAXParser.java:601)
at com.sun.org.apache.xerces.internal.impl.XMLDocumen tFragmentScannerImpl.scanEndElement(XMLDocumentFra gmentScannerImpl.java:1782)
at com.sun.org.apache.xerces.internal.impl.XMLDocumen tFragmentScannerImpl$FragmentContentDriver.next(XM LDocumentFragmentScannerImpl.java:2938)
at com.sun.org.apache.xerces.internal.impl.XMLDocumen tScannerImpl.next(XMLDocumentScannerImpl.java:648)
at com.sun.org.apache.xerces.internal.impl.XMLDocumen tFragmentScannerImpl.scanDocument(XMLDocumentFragm entScannerImpl.java:511)
at com.sun.org.apache.xerces.internal.parsers.XML11Co nfiguration.parse(XML11Configuration.java:808)
at com.sun.org.apache.xerces.internal.parsers.XML11Co nfiguration.parse(XML11Configuration.java:737)
at com.sun.org.apache.xerces.internal.parsers.XMLPars er.parse(XMLParser.java:119)
at com.sun.org.apache.xerces.internal.parsers.Abstrac tSAXParser.parse(AbstractSAXParser.java:1205)
at com.sun.org.apache.xerces.internal.jaxp.SAXParserI mpl$JAXPSAXParser.parse(SAXParserImpl.java:522)
at org.apache.commons.digester.Digester.parse(Digeste r.java:1871)
at CentroidGenerator.main(CentroidGenerator.java:137)
Caused by: java.lang.NullPointerException
at CentroidGenerator.nextItem(CentroidGenerator.java: 62)
at sun.reflect.GeneratedMethodAccessor7.invoke(Unknow n Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(De legatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.apache.commons.beanutils.MethodUtils.invokeMet hod(MethodUtils.java:216)
at org.apache.commons.digester.SetNextRule.end(SetNex tRule.java:220)
at org.apache.commons.digester.Rule.end(Rule.java:257 )
at org.apache.commons.digester.Digester.endElement(Di gester.java:1345)
... 12 more

thanks

What code do you have at CentroidGenerator.java: line 62?
Also check the API specs for the org.apache.commons.digester.Digester.parse method to see if they mentioned any conditions that may cause it to throw a NPE.

I've solved the issue was a row in the file. To solve the issue I've printed the source file rows while processing. However it has been possible only because the parsing takes 4 minutes.

I'm wondering how to debug such issues with a much bigger text file.

thanks

Juist assume that every line can be invalid and make sure that your code handles all possible invalid entries.