FULL PRODUCT VERSION :
every JDK version 6,7,8,9,10

A DESCRIPTION OF THE PROBLEM :
Inside com.sun.org.apache.xalan.internal.xsltc.trax.StAXEvent2SAX.handleEndElement(EndElement event)

The iterator from event.getNamespaces() returns `Namespace` objects, like in the function under it, except that the code tries to cast them to String.

The valid example is in the `handleStartElement` function below.


STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
The default implementation never has namespaces on the events, so you'll have to use org.codehaus.woodstox:woodstox-core-asl:4.3.0 to detect it


ERROR MESSAGES/STACK TRACES THAT OCCUR :
ERROR:  'org.codehaus.stax2.ri.evt.NamespaceEventImpl cannot be cast to java.lang.String'
javax.xml.transform.TransformerException: java.lang.ClassCastException: org.codehaus.stax2.ri.evt.NamespaceEventImpl cannot be cast to java.lang.String
	at com.sun.org.apache.xalan.internal.xsltc.trax.TransformerImpl.transform(TransformerImpl.java:746)
	at com.sun.org.apache.xalan.internal.xsltc.trax.TransformerImpl.transform(TransformerImpl.java:351)
	at javabugapplication.JavaBugApplication.main(JavaBugApplication.java:45)
Caused by: java.lang.ClassCastException: org.codehaus.stax2.ri.evt.NamespaceEventImpl cannot be cast to java.lang.String
	at com.sun.org.apache.xalan.internal.xsltc.trax.StAXEvent2SAX.handleEndElement(StAXEvent2SAX.java:341)
	at com.sun.org.apache.xalan.internal.xsltc.trax.StAXEvent2SAX.bridge(StAXEvent2SAX.java:198)
	at com.sun.org.apache.xalan.internal.xsltc.trax.StAXEvent2SAX.parse(StAXEvent2SAX.java:115)
	at com.sun.org.apache.xalan.internal.xsltc.trax.TransformerImpl.transformIdentity(TransformerImpl.java:682)
	at com.sun.org.apache.xalan.internal.xsltc.trax.TransformerImpl.transform(TransformerImpl.java:737)
	... 2 more
---------
java.lang.ClassCastException: org.codehaus.stax2.ri.evt.NamespaceEventImpl cannot be cast to java.lang.String
	at com.sun.org.apache.xalan.internal.xsltc.trax.StAXEvent2SAX.handleEndElement(StAXEvent2SAX.java:341)
	at com.sun.org.apache.xalan.internal.xsltc.trax.StAXEvent2SAX.bridge(StAXEvent2SAX.java:198)
	at com.sun.org.apache.xalan.internal.xsltc.trax.StAXEvent2SAX.parse(StAXEvent2SAX.java:115)
	at com.sun.org.apache.xalan.internal.xsltc.trax.TransformerImpl.transformIdentity(TransformerImpl.java:682)
	at com.sun.org.apache.xalan.internal.xsltc.trax.TransformerImpl.transform(TransformerImpl.java:737)
	at com.sun.org.apache.xalan.internal.xsltc.trax.TransformerImpl.transform(TransformerImpl.java:351)
	at javabugapplication.JavaBugApplication.main(JavaBugApplication.java:45)

REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
package javabugapplication;

import java.io.ByteArrayInputStream;
import java.io.InputStream;
import java.nio.charset.StandardCharsets;
import javax.xml.stream.XMLEventReader;
import javax.xml.stream.XMLInputFactory;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.dom.DOMResult;
import javax.xml.transform.stax.StAXSource;

import org.w3c.dom.Document;

public class JavaBugApplication {

	static String xml = "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n" +
"<root xmlns:h=\"http://www.w3.org/TR/html4/\" xmlns:f=\"https://www.w3schools.com/furniture\">\n" +
" <h:table>\n" +
"  <h:tr>\n" +
"    <h:td>Apples</h:td>\n" +
"    <h:td>Bananas</h:td>\n" +
"  </h:tr>\n" +
"</h:table>\n" +
"\n" +
"<f:table>\n" +
"  <f:name>African Coffee Table</f:name>\n" +
"  <f:width>80</f:width>\n" +
"  <f:length>120</f:length>\n" +
"</f:table>" +
"</root>";
	public static void main(String[] args) {
		Document theDoc = null;
		try (InputStream stream = new ByteArrayInputStream(xml.getBytes(StandardCharsets.UTF_8))) {
			XMLInputFactory xif = XMLInputFactory.newInstance();
			XMLEventReader eventReader = xif.createXMLEventReader( stream );
			TransformerFactory tf = TransformerFactory.newInstance();
			StAXSource src = new StAXSource(eventReader);
			Transformer transformer = tf.newTransformer();
			DOMResult result = new DOMResult();
			transformer.transform(src, result);
			theDoc = (Document) result.getNode();
		}
		catch (Throwable t) {
			t.printStackTrace();
		}
		assert(theDoc != null);
	}
	
}

---------- END SOURCE ----------

CUSTOMER SUBMITTED WORKAROUND :
Using different implementation of either factory