Hi,

At the moment there is no “automatic” way to do that _after_ the instace is created (i.e. after call to NodeManagerUaNode.createInstance or createNodeBuilder returns). However if you do add correct node manually to the instance node in question, it should work as-if it were configured to be instantiated _before_ those calls (for that see MyNodeManager.createAlarmNode in the SampleConsoleServer example). (There are some exceptions, e.g. if the InstanceDeclaration node did override something from the TypeDefinition or if there is special logic added to the afterCreate method of the Type in question)

As far as I’m aware, placeholder nodes are not that much used. 3.x codegen does create a List getter for the Types that have placeholders, which does return all subnodes of the node that have same TypeDefinition and ReferenceType that the placeholder node had. However there is no “special” support for them otherwise, but the Mandatory/OptionalPlaceholders only define that the node will have 0 or more (or at least one if mandatory) subnodes that have the same TypeDefinition and are added with same Reference than the placeholder node had. Therefore you can create instances of them with NodeManagerUaNode.createInstance and add them to the node with .addReference (of the manager or UaNode).

P.S. these apply to SDK 3.x; The Server Tutorial covers some of the above (but I’m aware that it should be better). Also maybe we can give better support for this in a future version.