public Collection<String> getDeniedParameters() throws GuacamoleException {
        return environment.getPropertyCollection(QUICKCONNECT_DENIED_PARAMETERS);
    }
Return the list of denied parameters for connections created using the
QuickConnect module, or null if none are defined (thereby allowing all
parameters to be set).

@return
    The list of parameters that cannot be set by connections created
    using the QuickConnect module.

@throws GuacamoleException 
    If guacamole.properties cannot be parsed.
extensions/guacamole-auth-quickconnect/src/main/java/org/apache/guacamole/auth/quickconnect/conf/ConfigurationService.java