7. How do I execute or run an XML file?
You can't and you don't. XML itself is not a programming language, so normal XML documents don't ‘run’ or ‘execute’. XML is a markup specification language and XML files are just data: they sit there until you run a program which displays them (like a browser) or does some work with them (like a converter which writes the data in another format, or a database which reads the data), or modifies them (like an editor).
If you want to view or display an XML file, open it with an XML editor or an XML browser.
The water is muddied by XSL (both XSLT and XSL:FO) which use XML syntax to implement a declarative programming language. In these special cases you can ‘execute’ an XML file, by running a processing application like Saxon, which compiles the directives specified in XSLT files into Java bytecode to process XML.



