java - org.xml.sax.SAXParseException: Premature end of file for *VALID* XML

Question

I am getting very strange "Premature end of file." exception for last few days on one of our servers. The same configuration XML works fine on another server. We are using Tomcat 5.0.28 on both these servers. This code has been working for ages (7+ years), only after recent server crash, we faced this problem on one of the servers. There is no change in XML as well as Java parsing code. :(

The only difference I can see is in Java versions -

Problem Server java version "1.6.0_16" Java(TM) SE Runtime Environment (build 1.6.0_16-b01) Java HotSpot(TM) 64-Bit Server VM (build 14.2-b01, mixed mode)

Working Server java version "1.6.0_07" Java(TM) SE Runtime Environment (build 1.6.0_07-b06) Java HotSpot(TM) 64-Bit Server VM (build 10.0-b23, mixed mode)

Here is the Java code that has been working for several years -

private void readSource(final InputSource in ) {
    try {
        DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
        DocumentBuilder db = dbf.newDocumentBuilder();
        Document doc = db.parse(in);
        Element elt = doc.getDocumentElement();

        this.readElement( elt );
    } catch ( Exception ex ) {
        ex.printStackTrace();
        throw new ConfigurationException( "Unable to parse configuration information", ex );
    }
}

And here is the exception.

[Fatal Error] :-1:-1: Premature end of file.
org.xml.sax.SAXParseException: Premature end of file.
        at org.apache.xerces.parsers.DOMParser.parse(Unknown Source)
        at org.apache.xerces.jaxp.DocumentBuilderImpl.parse(Unknown Source)
        at com.circus.core.Configuration.readSource(Configuration.java:706)

I have already tried validating XML and found no errors there. Any idea where else can I look for possible problem?

Any pointers would be highly appreciated!

TIA, - Manish

Answer 1

It is a problem with Java InputStream. When the stream is read once the file offset position counter is moved to the end of file. On the subsequent read by using the same stream you'll get this error. So you have to close and reopen the stream again or call inputStream.reset() to reset the offset counter to its initial position.