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https://issues.apache.org/jira/browse/DRILL-2570?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14381072#comment-14381072
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Daniel Barclay (Drill) commented on DRILL-2570:
-----------------------------------------------
Yes, it does seem to be a violation of Java's [service provider
mechanism|http://docs.oracle.com/javase/8/docs/technotes/guides/jar/jar.html#Service_Provider]
by Drill, because of a packaging inconsistency problem with the JDBC-all Jar
file (e.g., drill-jdbc-all-0.8.0-SNAPSHOT.jar):
That Jar file contains a file at
{{META-INF/services/javax.xml.parsers.SAXParserFactory}}, and that file says
"{{org.apache.xerces.jaxp.SAXParserFactoryImpl}}".
However, that Jar file does not contain the referenced class
{{org.apache.xerces.jaxp.SAXParserFactoryImpl}} (does not contain file
{{org/apache/xerces/jaxp/SAXParserFactoryImpl/class}}).
(Evidently:
- Java's {{javax.xml.parsers.SAXParserFactory.newInstance(...)}} uses Java's
service provider mechanism for configuration, to know which implementation of
{{SAXParserFactory}} to instantiate;
- that mechanism finds Drill's
{{META-INF/services/javax.xml.parsers.SAXParserFactory}} file; and
- either {{org.apache.xerces.jaxp.SAXParserFactoryImpl}} doesn't exist anywhere
on the class path, or, more likely, the mechanism looks only in the same Jar
file in which it found the {{.../services/...}} file and so doesn't find class
{{org.apache.xerces.jaxp.SAXParserFactoryImpl}} because Drill doesn't include
it in the Jar file.)
It seems that the tool and/or the configuration that Drill uses to repackage
the contents of original depended-on Jar files into JDBC-all doesn't understand
and/or isn't configured enough to keep SPM references and classes synchronized.
> Broken JDBC-All Jar packaging can cause missing XML classes
> -----------------------------------------------------------
>
> Key: DRILL-2570
> URL: https://issues.apache.org/jira/browse/DRILL-2570
> Project: Apache Drill
> Issue Type: Bug
> Reporter: Daniel Barclay (Drill)
> Attachments: ElementTraversal.rtf, xerces-error.rtf
>
>
> [Transcribed from other medium:]
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> When starting Spotfire Server using JDBC driver an error see attachment
> (xerces-error) is produced.
> This error is then resolved by adding the jars/3rdparty/xercesImpl-2.11.0.jar
> from the drillbit package to the classpath for the JDBC client driver.
> Then the following error is observed. See attachment (ElementTraversal).
> This requires to add jars/3rdparty/xml-apis-1.4.01.jar to the classpath from
> the drillbit package.
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> The issue is Tomcat and Spotfire Server does not show any errors and starts
> up fine without the Drill JDBC driver. Once the Drill driver is added the
> application server fails to start with the errors shown.
> Adding the 2 jars to the classpath then resolves the issue.
> I have not looked at all the JDBC driver classes, but it is important to note
> that the error occurs when the JDBC driver is added and resolved by adding 2
> jars from the drillbit package.
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> - - - - - - - - - - -
> > I do not see Drill classes in the stack trace. This seems to be a Tomcat
> > configuration issue.
> I suspect another possibility: that the Drill JDBC-all Jar file contains a
> stray reference to the unfound class (SAXParserFactoryImpl) in some file in
> META-INF/services (left over from some package whose classes we either
> excluded or renamed (with "shading")
> Xxx, Yyy: Can you try this?:
> (Temporarily) removing the added XML Jar files from the class path to
> re-confirm the problem.
> Move the Drill JDBC-all Jar file to be last on the class path (and remove
> ).
> Report whether the symptoms change.
> Thanks.
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