Hi,

If you can, it is easier to use com.prosysopc.ua.server.io.IoManagerAdapter instead and only override that method (unless you need others). That way SDK keeps handling internally the same as before you added the listener, as SDK also uses internally this mechanism to return Bad_NotReadable for some of the diagnostics nodes (the base nodes defined in the core namespace) when it is not enabled.

P.S.
Basically the IoManagerAdapter implementation just returns null for all object (including for the java.lang.Boolean) types and false for ‘boolean’ which does mean “this listener didn’t handle it, delegate to next”, you can of course do this manually as well, if you wish to implement the interface directly.