Re: Xindice 1.1: crash with NullPointerException

Hi Olle,

Looking at the exception stack trace, I would say that you've got =
problem with collection symbol table. That would explain your problems =
accessing all the documents.=20

I was able to reproduce exactly the same stack trace by intentionally =
modifying symbol table.=20

When Xindice saves a document to the collection, the document is =
compressed, which means that its element and attribute names are =
replaced with generated identifiers. The information about these =
identifiers saved in the collection symbol table. When retrieving the =
document, Xindice looks up the identifiers and replaces them with actual =
names. If it encounters identifier that cannot be found in the table... =
well, that exception is what happens.

I would suggest checking the symbol table first - it is just XML =
document that is located in /db/system/SysSymbols collection and =
document name is the same as collection path, but fragments of the path =
are separated with '_' instead of '/'. So, for collection /db/a/b/c it =
will be a_b_c.  Check if anything looks out of place, maybe you can see =
right away that some element or attribute names are missing...

This is an example of symbol table for SysConfig collection:
<?xml version=3D"1.0" encoding=3D"UTF-8"?>
<?xindice-class org.apache.xindice.xml.SymbolTable?>
<symbols>
  <symbol name=3D"filer" id=3D"6"/>
  <symbol name=3D"inline-metadata" id=3D"5"/>
  <symbol name=3D"compressed" id=3D"4"/>
  <symbol name=3D"name" id=3D"1"/>
  <symbol name=3D"indexes" id=3D"8"/>
  <symbol name=3D"class" id=3D"7"/>
  <symbol name=3D"collection" id=3D"2"/>
  <symbol name=3D"collections" id=3D"3"/>
  <symbol name=3D"database" id=3D"0"/>
</symbols>

Regards,
Natalia =20

On Jun 9, 2010, at 6:43 AM, Olle Olsson wrote:

> Suddenly this morning I could not access the data in Xindice ... =
execution exception.
>=20
> Running Xindice under Tomcat
> - Apache Tomcat/5.5.27
> - Xindice 1.1
> on a Linux box
>=20
> Symptoms:
> - Xindice is running under Tomcat (status seen in Tomcat Web =
Application Manager)
> - I can open the "Xindice Ugly Debug Tool"
> - I can navigate through the collection hierarchy
> - I can see that all documents exist
> - trying to inspect the contents of any document results in an =
exception
>=20
> That accessing *any* document generates that exception indicates to me =
that no single content file has been corrupted. And that all document =
files but no collection files have eroded, that is unlikely.
>=20
> Has some core central system-oriented file been perverted?
>=20
> Or is it a question of a bug in Xindice software?
>=20
> As to OS access restrictions, they all look good:
>   -rw-rw-r--+
> except for  SysAccess.tbl, SysGroups.tbl, SysObjects.tbl, and =
SysUsers.tbl, that have
>   -rwxr--r--+
> And there is no lack of available space on the file system.
>=20
>=20
> Extracts from logs reproduced below.
>=20
> *Question*:
> - Any hints/advise?
> - are there any diagnostic tools?
> - are there any repair tools?
>=20
> /olle
>=20
>=20
> ______________________
> localhost.2010-06-09.log
>=20
> Jun 9, 2010 12:04:48 PM org.apache.catalina.core.StandardWrapperValve =
invoke
> SEVERE: Servlet.service() for servlet xindice threw exception
> java.lang.NullPointerException
>    at =
org.apache.xindice.xml.dom.ElementImpl.checkLoaded(ElementImpl.java:110)
>    at =
org.apache.xindice.xml.dom.NodeImpl.getNodeName(NodeImpl.java:442)
>    at =
org.apache.xindice.xml.dom.ElementImpl.getTagName(ElementImpl.java:244)
>    at org.apache.xml.serialize.XMLSerializer.serializeElement(Unknown =
Source)
>    at =
org.apache.xml.serialize.BaseMarkupSerializer.serializeNode(Unknown =
Source)
>    at org.apache.xml.serialize.XMLSerializer.serializeElement(Unknown =
Source)
>    at =
org.apache.xml.serialize.BaseMarkupSerializer.serializeNode(Unknown =
Source)
>    at org.apache.xml.serialize.XMLSerializer.serializeElement(Unknown =
Source)
>    at =
org.apache.xml.serialize.BaseMarkupSerializer.serializeNode(Unknown =
Source)
>    at =
org.apache.xml.serialize.BaseMarkupSerializer.serializeNode(Unknown =
Source)
>    at org.apache.xml.serialize.BaseMarkupSerializer.serialize(Unknown =
Source)
>    at =
org.apache.xindice.server.UglyBrowser.prettyPrint(UglyBrowser.java:203)
>    at =
org.apache.xindice.server.UglyBrowser.getDetailView(UglyBrowser.java:192)
>    at org.apache.xindice.server.UglyBrowser.doGet(UglyBrowser.java:82)
>    at =
org.apache.xindice.server.XindiceServlet.doGet(XindiceServlet.java:84)
>    at javax.servlet.http.HttpServlet.service(HttpServlet.java:627)
>    at javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
>    at =
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(Applicati=
onFilterChain.java:269)
>    at =
org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilter=
Chain.java:188)
>    at =
org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.=
java:213)
>    at =
org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.=
java:172)
>    at =
org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:1=
27)
>    at =
org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:1=
17)
>    at =
org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:548)
>    at =
org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.ja=
va:108)
>    at =
org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:174=
)
>    at =
org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:875)=

>    at =
org.apache.coyote.http11.Http11BaseProtocol$Http11ConnectionHandler.proces=
sConnection(Http11BaseProtocol.java:665)
>    at =
org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoint.j=
ava:528)
>    at =
org.apache.tomcat.util.net.LeaderFollowerWorkerThread.runIt(LeaderFollower=
WorkerThread.java:81)
>    at =
org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.j=
ava:689)
>    at java.lang.Thread.run(Thread.java:619)
>=20
> ______________________
> catalina.out  (and  catalina.2010-06-09.log)
>=20
> Jun 9, 2010 12:04:48 PM org.apache.xindice.xml.dom.ElementImpl <init>
> WARNING: ignored exception
> java.lang.NullPointerException
>        at =
org.apache.xindice.xml.dom.ElementImpl.loadAttributes(ElementImpl.java:189=
)
>        at =
org.apache.xindice.xml.dom.ElementImpl.<init>(ElementImpl.java:66)
>        at =
org.apache.xindice.xml.dom.ContainerNodeImpl.loadChildren(ContainerNodeImp=
l.java:128)
>        at =
org.apache.xindice.xml.dom.ElementImpl.checkLoaded(ElementImpl.java:113)
>        at =
org.apache.xindice.xml.dom.NodeImpl.getNodeName(NodeImpl.java:442)
>        at =
org.apache.xindice.xml.dom.ElementImpl.getTagName(ElementImpl.java:244)
>        at =
org.apache.xml.serialize.XMLSerializer.serializeElement(Unknown Source)
>        at =
org.apache.xml.serialize.BaseMarkupSerializer.serializeNode(Unknown =
Source)
>        at =
org.apache.xml.serialize.XMLSerializer.serializeElement(Unknown Source)
>        at =
org.apache.xml.serialize.BaseMarkupSerializer.serializeNode(Unknown =
Source)
>        at =
org.apache.xml.serialize.BaseMarkupSerializer.serializeNode(Unknown =
Source)
>        at =
org.apache.xml.serialize.BaseMarkupSerializer.serialize(Unknown Source)
>        at =
org.apache.xindice.server.UglyBrowser.prettyPrint(UglyBrowser.java:203)
>        at =
org.apache.xindice.server.UglyBrowser.getDetailView(UglyBrowser.java:192)
>        at =
org.apache.xindice.server.UglyBrowser.doGet(UglyBrowser.java:82)
>        at =
org.apache.xindice.server.XindiceServlet.doGet(XindiceServlet.java:84)
>        at javax.servlet.http.HttpServlet.service(HttpServlet.java:627)
>        at javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
>        at =
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(Applicati=
onFilterChain.java:269)
>        at =
org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilter=
Chain.java:188)
>        at =
org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.=
java:213)
>        at =
org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.=
java:172)
>        at =
org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:1=
27)
>        at =
org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:1=
17)
>        at =
org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:548)
>        at =
org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.ja=
va:108)
>        at =
org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:174=
)
>        at =
org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:875)=

>        at =
org.apache.coyote.http11.Http11BaseProtocol$Http11ConnectionHandler.proces=
sConnection(Http11BaseProtocol.java:665)
>        at =
org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoint.j=
ava:528)
>        at =
org.apache.tomcat.util.net.LeaderFollowerWorkerThread.runIt(LeaderFollower=
WorkerThread.java:81)
>        at =
org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.j=
ava:689)
>        at java.lang.Thread.run(Thread.java:619)
> Jun 9, 2010 12:05:34 PM =
org.apache.xindice.core.DatabaseChangeObserver$FlushTask run
> INFO: Successfully flushed 0 collections out of 0
> .....
>=20
>=20
>=20
>=20
> --=20
> ------------------------------------------------------------------
> Olle Olsson   [email protected]   Tel: +46 8 633 15 19  Fax: +46 8 751 72 =
30
>        [Svenska W3C-kontoret: [email protected]]
> SICS [Swedish Institute of Computer Science]
> Box 1263
> SE - 164 29 Kista
> Sweden
> ------------------------------------------------------------------
>=20
>=20