org.xml.sax.SAXParseException: Content is not allowed in prolog

Question

I have a Java based web service client connected to Java web service (implemented on the Axis1 framework).

I am getting following exception in my log file:

Caused by: org.xml.sax.SAXParseException: Content is not allowed in prolog.
    at org.apache.xerces.util.ErrorHandlerWrapper.createSAXParseException(Unknown Source)
    at org.apache.xerces.util.ErrorHandlerWrapper.fatalError(Unknown Source)
    at org.apache.xerces.impl.XMLErrorReporter.reportError(Unknown Source)
    at org.apache.xerces.impl.XMLErrorReporter.reportError(Unknown Source)
    at org.apache.xerces.impl.XMLScanner.reportFatalError(Unknown Source)
    at org.apache.xerces.impl.XMLDocumentScannerImpl$PrologDispatcher.dispatch(Unknown Source)
    at org.apache.xerces.impl.XMLDocumentFragmentScannerImpl.scanDocument(Unknown Source)
    at org.apache.xerces.parsers.XML11Configuration.parse(Unknown Source)
    at org.apache.xerces.parsers.XML11Configuration.parse(Unknown Source)
    at org.apache.xerces.parsers.XMLParser.parse(Unknown Source)
    at org.apache.xerces.parsers.AbstractSAXParser.parse(Unknown Source)
    at javax.xml.parsers.SAXParser.parse(Unknown Source)
    at org.apache.axis.encoding.DeserializationContext.parse(DeserializationContext.java:227)
    at org.apache.axis.SOAPPart.getAsSOAPEnvelope(SOAPPart.java:696)
    at org.apache.axis.Message.getSOAPEnvelope(Message.java:435)
    at org.apache.ws.axis.security.WSDoAllReceiver.invoke(WSDoAllReceiver.java:114)
    at org.apache.axis.strategies.InvocationStrategy.visit(InvocationStrategy.java:32)
    at org.apache.axis.SimpleChain.doVisiting(SimpleChain.java:118)
    at org.apache.axis.SimpleChain.invoke(SimpleChain.java:83)
    at org.apache.axis.client.AxisClient.invoke(AxisClient.java:198)
    at org.apache.axis.client.Call.invokeEngine(Call.java:2784)
    at org.apache.axis.client.Call.invoke(Call.java:2767)
    at org.apache.axis.client.Call.invoke(Call.java:2443)
    at org.apache.axis.client.Call.invoke(Call.java:2366)
    at org.apache.axis.client.Call.invoke(Call.java:1812)

Answer 1

This is often caused by a white space before the XML declaration, but it could be any text, like a dash or any character. I say often caused by white space because people assume white space is always ignorable, but that's not the case here.

---

Another thing that often happens is a UTF-8 BOM (byte order mark), which is allowed before the XML declaration can be treated as whitespace if the document is handed as a stream of characters to an XML parser rather than as a stream of bytes.

The same can happen if schema files (.xsd) are used to validate the xml file and one of the schema files has an UTF-8 BOM.

Answer 2

Actually in addition to Yuriy Zubarev's Post

When you pass a nonexistent xml file to parser. For example you pass

new File("C:/temp/abc")

when only C:/temp/abc.xml file exists on your file system

In either case

builder = DocumentBuilderFactory.newInstance().newDocumentBuilder();
document = builder.parse(new File("C:/temp/abc"));

or

DOMParser parser = new DOMParser();
parser.parse("file:C:/temp/abc");

All give the same error message.

Very disappointing bug, because the following trace

javax.servlet.ServletException
    at org.apache.xerces.parsers.DOMParser.parse(Unknown Source)
...
Caused by: org.xml.sax.SAXParseException: Content is not allowed in prolog.
... 40 more

doesn't say anything about the fact of 'file name is incorrect' or 'such a file does not exist'. In my case I had absolutely correct xml file and had to spent 2 days to determine the real problem.

Answer 3

Try adding a space between the encoding="UTF-8" string in the prolog and the terminating ?>. In XML the prolog designates this bracket-question mark delimited element at the start of the document (while the tag prolog in stackoverflow refers to the programming language).

Added: Is that dash in front of your prolog part of the document? That would be the error there, having data in front of the prolog, -<?xml version="1.0" encoding="UTF-8"?>.