It is currently possible to specify the 'javax.security.jacc.policy.provider' system property, however it is not possible to specify a module.

From the JACC specification: -

_For each JRE of a J2EE 1.4 or later version Java EE application server, if the
system property
“javax.security.jacc.policy.provider
” is defined,
the application server must construct an
instance of the class identified by the
system property, confirm that the
resulting object is an instance of
java.security.Policy,
and set, by calling the
java.security.Policy.setPolicy
method, the resulting object as the
corresponding Policy object u
sed by the JRE. _

The specification only specifies that the system property identifies the class, it does not specify how.

In it's simplest form we should assume this is just a class name, in a more complex form we should allow the module to be specified.