mail/src/main/java/org/jboss/as/mail/extension/MailSessionAdd.java
@Override
    protected void performRuntime(OperationContext context, ModelNode operation, ModelNode model) throws OperationFailedException {
        final PathAddress address = context.getCurrentAddress();
        ModelNode fullTree = Resource.Tools.readModel(context.readResource(PathAddress.EMPTY_ADDRESS));
        installRuntimeServices(context, address, fullTree);
    }
@Override
    protected void performRuntime(OperationContext context, ModelNode operation, ModelNode model) throws OperationFailedException {
        final PathAddress address = context.getCurrentAddress();
        ModelNode fullTree = Resource.Tools.readModel(context.readResource(PathAddress.EMPTY_ADDRESS));
        installRuntimeServices(context, address, fullTree);
    }
Make any runtime changes necessary to effect the changes indicated by the given {@code operation}. E
<p>
It constructs a MailSessionService that provides mail session and registers it to Naming service.
</p>

@param context             the operation context
@param operation           the operation being executed
@param model               persistent configuration model node that corresponds to the address of {@code operation}
@throws org.jboss.as.controller.OperationFailedException
if {@code operation} is invalid or updating the runtime otherwise fails