So today when I went to validate some xml's against a Xsd I was a bit surprised when it didn't work
What was more surprising was that it was working, and when I changed something small, it stopped.
As part of a Unit Test I was validating an xml file against a schema, and it was working fine. However I was loading the Xsd via a webserver into the parser. This wouldn't do since other developpers would want to run the unit tests and would not want the hassle of starting up a webserver and dropping the xsd file in place initally before running the tests.
So I changed the URL to load the Xsd via the file:// protocal. See below
Running that however gave the following exception
org.xml.sax.SAXParseException: cvc-elt.1: Cannot find the declaration of element 'wishList'.
at org.apache.xerces.util.ErrorHandlerWrapper.createSAXParseException(Unknown Source)
But I knew the XSD was correct because it had been working before when I retrieved it via http:// on my webserver....
Do you see the problem? Well I didn't initially. After some poking around I found the solution.
See the difference. Subtle isn't it. Basically xerces insists that file needs 3 forward slashes in it url definition (file:///wishlist.xsd). That was the problem. Surely a better error message could have been generated there. (Maybe XSD not found or something)
Anyway I then started gettign the following error
org.xml.sax.SAXParseException: Invalid byte 1 of 1-byte UTF-8 sequence.
at org.apache.xerces.parsers.DOMParser.parse(Unknown Source)
Short answer to this problem was my file character encoding. I had saved my xsd using a free editor (crimson). By default it saves files in Ascii encoding. However my Xsd expected to be in UTF-8. Changing the character encoding and re-saving solved the problem.
Amazing how a simple little task can tie you down for hours..