Attempt to create an XMLReader from system defaults. In environments which can support it, the name of the XMLReader class is determined by trying each these options in order, and using the first one which succeeds:

• If the system property org.xml.sax.driver has a value, that is used as an XMLReader class name.
• The JAR "Services API" is used to look for a class name in the META-INF/services/org.xml.sax.driver file in jarfiles available to the runtime.
• SAX parser distributions are strongly encouraged to provide a default XMLReader class name that will take effect only when previous options (on this list) are not successful.
• Finally, if ParserFactory.MakeParser can return a system default SAX1 parser, that parser is wrapped in a Org.Xml.Sax.Helpers.ParserAdapter. (This is a migration aid for SAX1 environments, where the org.xml.sax.parser system property will often be usable.)

In environments such as small embedded systems, which can not support that flexibility, other mechanisms to determine the default may be used.

Note that many Java environments allow system properties to be initialized on a command line. This means that in most cases setting a good value for that property ensures that calls to this method will succeed, except when security policies intervene. This will also maximize application portability to older SAX environments, with less robust implementations of this method.

[Android Documentation]