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https://issues.apache.org/jira/browse/XERCESJ-814?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12883577#action_12883577
]
Jesse Glick commented on XERCESJ-814:
-------------------------------------
It's going on two years since a patch to correct this bug was suggested; is
anyone taking it?
DTDDVFactory seems to suffer from a similar problem according to
http://netbeans.org/bugzilla/show_bug.cgi?id=187728
The code
private static final String DEFAULT_FACTORY_CLASS =
"org.apache.xerces.impl.dv.dtd.DTDDVFactoryImpl";
public static final DTDDVFactory getInstance() throws DVFactoryException {
return getInstance(DEFAULT_FACTORY_CLASS);
}
should likely be replaced with the simpler and safer
public static DTDDVFactory getInstance() {
return new org.apache.xerces.impl.dv.dtd.DTDDVFactoryImpl();
}
and code calling
DTDDVFactory.getInstance(XML11_DATATYPE_VALIDATOR_FACTORY)
should be changed to use
new org.apache.xerces.impl.dv.dtd.XML11DTDDVFactoryImpl()
so there is no real need for either of the getInstance methods. SchemaDVFactory
is similar, so it is probable that org.apache.xerces.impl.dv.ObjectFactory
could just be deleted, greatly simplifying the code: it is never used to load a
user-configurable service.
There are other places where excessively flexible class loading is used; for
example, XIncludeHandler has the rather roundabout code:
public final static String XINCLUDE_DEFAULT_CONFIGURATION =
"org.apache.xerces.parsers.XIncludeParserConfiguration";
...
String parserName = XINCLUDE_DEFAULT_CONFIGURATION;
if (xpointer != null)
parserName =
"org.apache.xerces.parsers.XPointerParserConfiguration";
fChildConfig =
(XMLParserConfiguration)ObjectFactory.newInstance(
parserName,
ObjectFactory.findClassLoader(),
true);
which could be greatly simplified:
fChildConfig = xpointer != null ? new
org.apache.xerces.parsers.XPointerParserConfiguration() : new
org.apache.xerces.parsers.XIncludeParserConfiguration();
again removing the need for org.apache.xerces.xinclude.ObjectFactory entirely.
> Use of ContextClassLoader is not appropriate
> --------------------------------------------
>
> Key: XERCESJ-814
> URL: https://issues.apache.org/jira/browse/XERCESJ-814
> Project: Xerces2-J
> Issue Type: Bug
> Components: JAXP (javax.xml.parsers)
> Affects Versions: 2.5.0
> Environment: Operating System: Other
> Platform: Other
> Reporter: Thomas Pasch
> Assignee: Xerces-J Developers Mailing List
>
> On jdk >=1.2 (but <1.4) xerces uses the ContextClassLoader to load classes of
> its own distribution. This is never appropriate and will lead to
> ClassCastException in a J2EE setting.
> For loading classes of its own distribution, the (current) ClassLoader that
> has
> loaded the distribution classes (i.e. xercesImpl.jar) should be used.
> Glory Details:
> --------------
> The problem shows up when there is a (outdated) xerces in your (ClassLoader)
> path but you want to use a newer version of xerces in your application. Note
> that this is NOT an obscure setting but the normal case in every J2EE (1.3)
> application because you are guarantied to have JAXP XML access, but often to
> an
> outdated product (in my case I'm using IBM WAS 5.0.1 on Solaris).
> One of the possible solution is to load the JAXP factory classes by a self
> created (URL)ClassLoader. (Note that this is not 100% to the specs but works
> on
> most application servers I know.)
> The problem however arises from within xerces. It exist in some variants but
> basically boils down to the following:
> 1.
> While creating a SAX/DOM object xerces creates a XMLParserConfiguration
> first.
> For example, when trying to instantiate a
> org.apache.xerces.jaxp.DocumentBuilderImpl (by means of
> org.apache.xerces.jaxp.DocumentBuilderFactoryImpl) first a
> XMLParserConfiguration is created by org.apache.xerces.util.ObjectFactory
> invoked by org.apache.xerces.parsers.DOMParser(SymbolTable, XMLGrammarPool).
> 2.
> ObjectFactory.findClassLoader(), however, uses the ContextClassLoader to load
> the Class "org.apache.xerces.xni.parser.XMLParserConfiguration". BUMMER! This
> is the (outdated) class of the old version of xerces.
> 3.
> Xerces 2.5.0 fails miserably because of a ClassCastException. Typical
> stacktrace is:
> java.lang.IllegalArgumentException:
> org.apache.xerces.parsers.StandardParserConfiguration
> at org.apache.xerces.jaxp.DocumentBuilderFactoryImpl.setAttribute
> (DocumentBuilderFactoryImpl.java:128)
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