GWT2.8 : org.apache.xerces.parsers.XIncludeAwareParserConfiguration cannot be cast to org.apache.xerces.xni.parser.XMLParserConfiguration

[Darren Smith]

Hi,

I am developing a <web-app> that contains within it

  - a vanilla HttpServlet

  - a GWT RPC Service implementation (RemoteServiceServlet) 

I am currently using [GWT2.8rc1].

Both servlets manipulate XML documents, and hence make calls to the following code

DocumentBuilderFactory docfactory = DocumentBuilderFactory.newInstance();

docfactory.setNamespaceAware(true); 

DocumentBuilder builder = docfactory.newDocumentBuilder();   // * problem here *

When I launch the application in Eclipse, using the embedded Jetty container, the vanilla HttpServlet will fail at the line

DocumentBuilder builder = docfactory.newDocumentBuilder();   // * problem here *

The error message is 

  java.lang.ClassCastException: org.apache.xerces.parsers.XIncludeAwareParserConfiguration cannot be cast to org.apache.xerces.xni.parser.XMLParserConfiguration

Having done some research, this exception is typically raised when there are several Xerces implementations found on the classpath.

(I can only see Xerces implementations in gwt-dev and in Eclipse as a plugin).

For the GWT RPC Service implementation, launched as part of the same <web-app>, the XML document processing works fine - i.e. no exception raised.

If I comment out in the web.xml file the GWT-RPC servlet defintion, then the vanilla HttpServlet will perform the XML document processing without an exception.

Has anyone encountered similar problems?

Darren Smith.

[Ian Whyman]

Hi Darren,

We are seeing the same issue, did you find any resolution?

Regards,

Ian

[Drew Spencer]

Hey guys, this might help you. I had an issue with an old Xerces on the path before: http://stackoverflow.com/questions/38457973/cant-compile-gwt-app-using-2-8-0-snapshot-and-java-8-with-gwt-maven-plugin

Happy coding!

Drew

[Darren Smith]

Hi Ian,

Yes, we are still seeing the problem. I've put it aside for the moment, hoping to revisit once we upgrade to a new GWT Release Candidate.

Glad to know I'm not the only one suffering from this :)

Cheers

Darren

[Ian Whyman]

It seems still to be an issue with the final 2.8.0 release

Ian

[Peter Petranik]

Hi, I have a same problem after I updated my application from GWT 2.7 to 2.8

That is the code that raises the exception:
DocumentBuilderFactory.newInstance().newDocumentBuilder()

And that is the exception: 

java.lang.ClassCastException: org.apache.xerces.parsers.XIncludeAwareParserConfiguration cannot be cast to org.apache.xerces.xni.parser.XMLParserConfiguration

at org.apache.xerces.parsers.DOMParser.<init>(Unknown Source)

at org.apache.xerces.parsers.DOMParser.<init>(Unknown Source)

at org.apache.xerces.jaxp.DocumentBuilderImpl.<init>(Unknown Source)

at org.apache.xerces.jaxp.DocumentBuilderFactoryImpl.newDocumentBuilder(Unknown Source)
...

Has somebody already found some solution how to fix that ?

[Juan Pablo Gardella]

Try by removing/exluding (if you have it in you r dependencies) xerces. 

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[Peter Petranik]

I have the Xerces library as dependency as part of gwt-dev.jar that is set by GWT SDK. I am not using the maven for a project. My dependencies are defined just by Eclipse in Project Settings (check the screenshot)

Am Donnerstag, 6. Oktober 2016 09:20:49 UTC+2 schrieb Darren Smith:

[Juan Pablo Gardella]

Check http://stackoverflow.com/questions/24805360/classcastexception-org-apache-xerces-parsers-xincludeawareparserconfiguration-c

[Ian Whyman]

In the end we fixed that by shipping our own version of xerces & co in our war.

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Ian Whyman

[Adam Gerbert]

Ran into the same issue after upgrading to 2.8 from 2.7. Only happened in super dev mode, as the xerces dependency was coming from gwt-dev.jar. I fixed it in the same manner as Ian Whyman (thanks!), by including the dependency explicitly. 

[Peter Petranik]

I found the solution for my problem with this exception, according to Javadoc and databasesandlife.com I have used two system properties and problem was gone, because our code was written to use JDK xerces

-Djavax.xml.parsers.DocumentBuilderFactory=com.sun.org.apache.xerces.internal.jaxp.DocumentBuilderFactoryImpl
-Djavax.xml.parsers.SAXParserFactory=com.sun.org.apache.xerces.internal.jaxp.SAXParserFactoryImpl

[Leto]

Am Dienstag, 25. Oktober 2016 14:21:40 UTC+2 schrieb Ian Whyman:

It seems still to be an issue with the final 2.8.0 release

Ian

I recently upgraded to GWT 2.8.2 (from the old version 2.6.0) I ran into the same problem ("org.apache.xerces.parsers.XIncludeAwareParserConfiguration cannot be cast to org.apache.xerces.xni.parser.XMLParserConfiguration").

What I would like to understand is, is the Xerces version packaged with GWT 2.8.2 (gwt-dev.jar) incompatible? The fix with 

-Djavax.xml.parsers.DocumentBuilderFactory=com.sun.org.apache.xerces.internal.jaxp.DocumentBuilderFactoryImpl
-Djavax.xml.parsers.SAXParserFactory=com.sun.org.apache.xerces.internal.jaxp.SAXParserFactoryImpl

seems to work.

So are we talking about a kind of dependency-problem with GWT (2.8.0+)?

[Thomas Broyer]

What's in your classpath? There might probably be ways to avoid those situations, in GWT, but so few people have run into this that no one investigated further.

[Leto]

Am Samstag, 30. Juni 2018 14:35:17 UTC+2 schrieb Thomas Broyer:

What's in your classpath? There might probably be ways to avoid those situations, in GWT, but so few people have run into this that no one investigated further.

I stripped down my dependencies to just only a few, and if I omit the 

> -Djavax.xml.parsers.DocumentBuilderFactory=com.sun.org.apache.xerces.internal.jaxp.DocumentBuilderFactoryImpl

> -Djavax.xml.parsers.SAXParserFactory=com.sun.org.apache.xerces.internal.jaxp.SAXParserFactoryImpl

arguments, the problem still occurs.

I use the simple Ant script, no Eclipse, no Maven in this setup. And within my Ant script, I print the current classpath, which results in:

> D:\[...]\gwt-2.8.2\gwt-user.jar

> D:\[...]\gwt-2.8.2\gwt-dev.jar

> D:\[...]\Eclipse\MyGwtApp\src

> D:\[...]\Eclipse\MyGwtApp\war\WEB-INF\classes

> D:\[...]\Eclipse\MyGwtApp\war\WEB-INF\lib

> D:\[...]\Eclipse\MyGwtApp\war\WEB-INF\lib\aopalliance-1.0.jar

> D:\[...]\Eclipse\MyGwtApp\war\WEB-INF\lib\gin-2.1.2.jar

> D:\[...]\Eclipse\MyGwtApp\war\WEB-INF\lib\guice-3.0.jar

> D:\[...]\Eclipse\MyGwtApp\war\WEB-INF\lib\guice-assistedinject-3.0.jar

> D:\[...]\Eclipse\MyGwtApp\war\WEB-INF\lib\gwt-visualization-1.1.2.jar

> D:\[...]\Eclipse\MyGwtApp\war\WEB-INF\lib\javax.inject-1.jar 

[Slava Pankov]

For me the following helps in my project's pom.xml:

    <!-- for unknown reason GWT 2.8 debugging under Eclipse fails without xerces dependency -->

    <dependency> 

      <groupId>xerces</groupId>

      <artifactId>xercesImpl</artifactId>

      <version>2.11.0</version>

    </dependency>