After a servlet that I wrote using Xerces has been running for an
undetermined amount of time (I'm not sure what conditions trigger this), I
get the following exception that comes up *every* time I run my servlet
from then on, until I restart the server:
- <exception lang="java">
<type>java.lang.NullPointerException</type>
<message />
- <stacktrace>
<p>java.lang.NullPointerException</p>
<p>at
org.apache.xerces.dom.DeferredDocumentImpl.synchronizeChildren(DeferredDocumentImpl.java:1218)</p>
<p>at
org.apache.xerces.dom.DocumentImpl.getDocumentElement(DocumentImpl.java:456)</p>
<p>at net.press.pa.storymanager.Frontend.execute(Frontend.java:63)</p>
<p>at
net.press.pa.storymanager.servlets.SMInterface.doGet(SMInterface.java:208)</p>
<p>at javax.servlet.http.HttpServlet.service(HttpServlet.java:499)</p>
<p>at javax.servlet.http.HttpServlet.service(HttpServlet.java:588)</p>
<p>at
org.apache.jserv.JServConnection.processRequest(JServConnection.java:314)</p>
<p>at org.apache.jserv.JServConnection.run(JServConnection.java:188)</p>
<p>at java.lang.Thread.run(Thread.java:479)</p>
</stacktrace>
</exception>
(This is an XML pretty-printing of the exception as done by my servlet).
The line of code this refers to is:
node.parentNode = this;
and 'node' was set by a call: NodeImpl node = (NodeImpl)getNodeObject(index);
I notice the getNodeObject can return null:
// is there anything to do?
if (nodeIndex == -1) {
return null;
}
but a null return value is not checked for in synchronizedChildren().
Can anyone suggest why this is happening and how I can fix it?
Many thanks,
Matt.
