public String getContextFactoryClassName() {
        return (String) getEnvironmentProperty(Context.INITIAL_CONTEXT_FACTORY);
    }
Sets the name of the ContextFactory class to use. This defaults to the SUN LDAP JNDI implementation
but can be overridden to use custom LDAP factories.
<p/>
This is a wrapper method for getting the JNDI environment's {@link Context#INITIAL_CONTEXT_FACTORY} property.

@return the name of the ContextFactory class to use.
core/src/main/java/org/apache/shiro/realm/ldap/JndiLdapContextFactory.java