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:

Answer 1

If all else fails, open the file in binary to make sure there are no funny characters [3 non printable characters at the beginning of the file that identify the file as utf-8] at the beginning of the file. We did this and found some. so we converted the file from utf-8 to ascii and it worked.

Answer 2

I took code of Dineshkumar and modified to Validate my XML file correctly:

import org.apache.log4j.Logger;

public class Myclass{

private static final Logger LOGGER = Logger.getLogger(Myclass.class);

/**
 * Validate XML file against Schemas XSD in pathEsquema directory
 * @param pathEsquema directory that contains XSD Schemas to validate
 * @param pathFileXML XML file to validate
 * @throws BusinessException if it throws any Exception
 */
public static void validarXML(String pathEsquema, String pathFileXML) 
	throws BusinessException{	
	String W3C_XML_SCHEMA = "http://www.w3.org/2001/XMLSchema";
	String nameFileXSD = "file.xsd";
	String MY_SCHEMA1 = pathEsquema+nameFileXSD);
	ParserErrorHandler parserErrorHandler;
	try{
		SchemaFactory schemaFactory = SchemaFactory.newInstance(W3C_XML_SCHEMA);
		
		Source [] source = { 
			new StreamSource(new File(MY_SCHEMA1))
			};
		Schema schemaGrammar = schemaFactory.newSchema(source);

		Validator schemaValidator = schemaGrammar.newValidator();
		schemaValidator.setErrorHandler(
			parserErrorHandler= new ParserErrorHandler());
		
		/** validate xml instance against the grammar. */
		File file = new File(pathFileXML);
		InputStream isS= new FileInputStream(file);
		Reader reader = new InputStreamReader(isS,"UTF-8");
		schemaValidator.validate(new StreamSource(reader));
		
		if(parserErrorHandler.getErrorHandler().isEmpty()&& 
			parserErrorHandler.getFatalErrorHandler().isEmpty()){
			if(!parserErrorHandler.getWarningHandler().isEmpty()){
				LOGGER.info(
				String.format("WARNING validate XML:[%s] Descripcion:[%s]",
					pathFileXML,parserErrorHandler.getWarningHandler()));
			}else{
				LOGGER.info(
				String.format("OK validate  XML:[%s]",
					pathFileXML));
			}
		}else{
			throw new BusinessException(
				String.format("Error validate  XML:[%s], FatalError:[%s], Error:[%s]",
				pathFileXML,
				parserErrorHandler.getFatalErrorHandler(),
				parserErrorHandler.getErrorHandler()));
		}		
	}
	catch(SAXParseException e){
		throw new BusinessException(String.format("Error validate XML:[%s], SAXParseException:[%s]",
			pathFileXML,e.getMessage()),e);
	}
	catch (SAXException e){
		throw new BusinessException(String.format("Error validate XML:[%s], SAXException:[%s]",
			pathFileXML,e.getMessage()),e);
	}
	catch (IOException e) {
		throw new BusinessException(String.format("Error validate XML:[%s], 
			IOException:[%s]",pathFileXML,e.getMessage()),e);
	}
	
}

}

Answer 3

Try with BOMInputStream in apache.commons.io:

public static <T> T getContent(Class<T> instance, SchemaType schemaType, InputStream stream) throws JAXBException, SAXException, IOException {

    JAXBContext context = JAXBContext.newInstance(instance);
    Unmarshaller unmarshaller = context.createUnmarshaller();
    Reader reader = new InputStreamReader(new BOMInputStream(stream), "UTF-8");

    JAXBElement<T> entry = unmarshaller.unmarshal(new StreamSource(reader), instance);

    return entry.getValue();
}

Answer 4

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 5

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 6

What i have tried [Did not work]

In my case the web.xml in my application had extra space. Even after i deleted ; it did not work!.

I was playing with logging.properties and web.xml in my tomcat, but even after i reverted the error persists!.

Solution

To be specific i tried do adding

org.apache.catalina.filters.ExpiresFilter.level = FINE

Tomcat expire filter is not working correctly