XSQL SVG Example questions

Question

The SVG example provided with the XSQL servlet is excellent and illustrates at least 5 different (and very useful) techniques. Congrats to whoever came up with it.
This one example shows SVG, named templates, use of xsl:variable, use of xsl_param, use of xsl:with-param, use of xsl:call-template and the apparent use of java classes from a jar file ala java server pages.
The example also raises several questions:
1. The example uses two namespace declarations I haven't seen before -
xmlns:Color="http://www.oracle.com/XSL/Transform/java/java.awt.Color"
and
xmlns:Integer="http://www.oracle.com/XSL/Transform/java/java.lang.Integer"
These appear to be allowing the use of Java classes in some jar file similar to the way Java server pages might do it.
It this correct? Is this because these two classes were built-in to the XSQL servlet? What other classes can be used? All of them? From any jar file? Is more documentation available?
2. What does the 'doctype=system="svg-19990812.dtd"' line do? There is no such DTD on my system but the demo works fine. There are references to DTDs with similar names in the FOP samples and in Adobe's samples but the name is slightly different.
3. Why is the media-type image/svg? The SVG 1.0 spec dated 2 Nov 2000 in section 1.2 says the SVG mime type is "image/svg+xml".
4. Why is there no namespace declaration for the svg tag or any of the svg related tags? Samples from other vendors seem to always have a declaration.
Thanks again for a great piece of code.
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Answer 1

Rick,
You'll find a further-refined, and fully-explained version of the SVG example in Chapter 16 of Building Oracle XML Applications. This chapter covers the use of XSLT extension functions and illustrates how to use Java extension functions with the Oracle XSLT engine.
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[*]The two namespaces you list are the way that the Oracle XSLT engine allows you to map extension functions in a namespace to methods of a Java class. This example illustrates using two different built-in classes of the JDK, java.awt.Color and java.lang.Integer. These are not specific to (or built-in in any way to the) XSQL processor or the XSLT engine, but are base classes in the JDK. You can use any Java extension functions in your XSLT stylesheets. The only requirement is that you (1) get the namespace correct to assign a namespace to the appropriate fully-qualified classname, and (2) make sure the classes you want to use are in the CLASSPATH.
[*]The <xsl:output> attribute doctype-system provides a value to be used for the SYSTEM URI of the <!DOCTYPE in the transformed output. The particular value was required by the SVG draft at the time I built the demo. It must be handled by a special entity-resolver built into the SVG Viewer that you're using, which explains why not having on your system as a physical file doesn't stop the demo from working.
[*]The media-type is image/svg instead of image/svg+xml because the SVG demo was built before the final draft of SVG went out. This value was apparently changed in one of the final drafts. It appears that the Adobe SVG viewer registers itself as the handler for both.
[*]See http://www.w3.org/TR/SVG/struct.html#NewDocument. The spec appears to allow both unqualified use of <svg> as well as namespace-qualified <svg:svg> when SVG is embedded within another document.
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