Returns a property associated with a specified path name. All properties
exported by this object must have a name which is a valid Java identifier.
Specifying one of these names causes the corresponding Property to be
returned. Handles to subproperties can also be obtained by delimiting the
sub-property name(s) by '.' characters. A sub-property
exists if the value of a property is itself an object which exports
properties. It is only possible to obtain a sub-property handle if each of
its ancestor properties exports their values by reference.