The JspFactory is an abstract class that defines a number of factory
methods available to a JSP page at runtime for the purposes of creating
instances of various interfaces and classes used to support the JSP
A conformant JSP Engine implementation will, during it's initialization
instantiate an implementation dependent subclass of this class, and make
it globally available for use by JSP implementation classes by registering
the instance created with this class via the
static setDefaultFactory() method.
The PageContext and the JspEngineInfo classes are the only implementation-dependent
classes that can be created from the factory.
JspFactory objects should not be used by JSP page authors.