Xerces SAXParser validation problems

Question

I'm using the Xerces 2 beta 3 SAXParser to validate an XML document but
it does not seem to raise a SAXParseException even though my XML is not valid.
Say I have the following DTD, example.dtd:
<?xml version='1.0' encoding='UTF-8' ?>
<!ELEMENT a (b)>
<!ELEMENT b (c)>
<!ELEMENT c (#PCDATA)>
Now, I have a well-formed XML document that is not valid because it clearly violates
the DTD above:
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE class SYSTEM "example.dtd">
<a>
<c>Hello</c>
</a>
It is my understanding that the SAXParser validation should catch this invalid XML.
Why does it not raise any Exceptions?
From what I understood the only valid documents should contain 0 or more of the
following XML statements:
<c>Hello</c>
OR
<b>
<c>Hello</c>
</b
OR
<a>
<b>
<c>Hello</c>
</b>
</a>
Also, note that if I forget a tag, the parser behaves as expected and raises a SAXParseException that reads
'The element type "a" must be terminated by the matching end-tag "</a>'
i.e. <c>Hello
The only reason I mention this is to show that validation is set to true on the SAXParser.
Any help would be greatly appreciated. Thanks in advance.
KL

Answer 1

The problem I am have does not seem to be with the value of the
http://xml.org/sax/features/validation feature. I printed the value out after I set it and it is indeed set to true.
I was reading more about the feature (see below) and am now thinking the validation might not occur because the grammar might not be read in by the parser.
When that say "grammar" I assume they mean the DTD in my case. When they say "the document must specify a grammar," I assume that mean that my XML document must state the DTD to use in the DOCTYPE statement.
My XML document looks kind of like this:
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE class SYSTEM "example.dtd" [
<!ENTITY % entities SYSTEM "7670Entities2.0.xml">
%entities;
]>
<a>
<b>
<c>Hello</c>
</b>
</a>
So have I specified the grammar correctly? Is there anyway to print out anything that will show that the grammar has indeed been read in?
http://xml.org/sax/features/validation
True:
Validate the document.
False:
Do not validate the document.
Default:
false
Access:
(parsing) read-only; (not parsing) read-write;
Note:
If this feature is set to true, the document must specify a
grammar. If this feature is set to false, the document may
specify a grammar and that grammar will be parsed but
no validation of the document contents will be performed.