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Java parsing XML document gives "Content not allowed in prolog." error

Answer 1

+1 A:

The document looks fine to me but I suspect that it contains invisible characters. Open it in a hex editor to check that there really isn't anything before the very first "<". Make sure the spaces in the XML header are spaces. Maybe delete the space before "?>". Check which line breaks are used.

Make sure the document is proper UTF-8. Some windows editors save the document as UTF-16 (i.e. every second byte is 0).

Aaron Digulla 2010-04-08 12:56:48

I've been editing the XML file in Eclipse text editor. I'm on a Mac and I also use BBEdit. I'll check for invisible characters.

thechiman 2010-04-08 13:00:31

I checked for invisible characters in BBEdit (View > Text Display > Show Invisibles) and I don't see any invisible characters in the XML declaration. I also deleted the whitespace at the end of the declaration.I added encoding="UTF-8" and encoding="UTF-16 and I'm still getting the error.

thechiman 2010-04-08 13:08:16

What is the encoding of the file? i.e. not what you think but what does your editor say?

Aaron Digulla 2010-04-08 13:53:21

Also make sure that you're actually looking at the file which causes the error!

Aaron Digulla 2010-04-08 13:54:02

I checked the encoding type in BBEdit; it is UTF-16.I'm pretty sure I'm looking at the right file. The following is my code for reading in the file and parsing it:File f = new File("/Users/thechiman/Dropbox/introcs/PSU SOC Crawler/src/resources"); //Check to see if file exists if(f.exists()) { System.out.println("file exists"); } else { System.out.println("file does not exist"); } //Use factory to get a new DocumentBuilder DocumentBuilder db = dbf.newDocumentBuilder(); //Parse the XML file, get DOM representation this.dom = db.parse(f);

thechiman 2010-04-08 14:59:41

Well, the parser expects UTF-8 and your file is UTF-16. This means the first byte of the file is 0 and you get the error. Save the file with the correct encoding (UTF-8) to fix the problem.

Aaron Digulla 2010-04-08 15:21:53

I saved the file as UTF-8 and UTF-8, No BOM. Both times I get the same error.

thechiman 2010-04-08 15:54:53

In that case, you're editing a different file than the parser reads.

Aaron Digulla 2010-04-09 07:18:54

Answer 2

+1 A:

Make sure there's no hidden whitespace at the start of your XML file. Also maybe include encoding="UTF-8" (or 16? No clue) in the node.

Ben J 2010-04-08 12:57:58

This is unfortunately most likely the cause.

Esko 2010-04-08 13:02:29

Checked in BBEdit for hidden characters and added the encoding attribute to the XML declaration. Both didn't fix it.

thechiman 2010-04-08 13:09:14

Answer 3

A:

If you're able to control the xml file, try adding a bit more information to the beginning of the file:

<?xml version="1.0" encoding="UTF-16" standalone="no"?>

Drew Johnson 2010-04-08 16:22:41

I've added both standalone="no" and standalone="yes". Both give me the same error.

thechiman 2010-04-08 16:37:15

hmmm...the next thing I'd try is brute force - try to get a dummy document through the parser, then slowly add parts of your original document until you can identify the problem. I've been down that road before :-)

Drew Johnson 2010-04-08 16:55:57

Answer 4

A:

Check any syntax problem in the XMl file. I've found this error when working on xsl/xsp with Cocoon and I define a variable using a non-existing node or something like that. Check the whole XML.

Alfabravo 2010-04-08 16:29:42

I get the error before I can do anything with the parsed document. It's failing when I call DocumentBuilder.parse(XMLFile). I ran the XML file through an XML validator (xmlvalidation.com) and it went through just fine.

thechiman 2010-04-08 16:42:44

Is the file available in the specified location? Maybe your program can't access the content of the file and the parser just says what it founds is not xml valid... just guessing.

Alfabravo 2010-04-08 21:17:30

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Java parsing XML document gives "Content not allowed in prolog." error

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