What exactly do you mean with 'Repository node'?
Let's assume you mean the 'Company Home' node:
In the Maven Platform Jar archetype, there is an example where the 'Company Home' node is retrieved via the `nodeLocatorService` as follows:
nodeLocatorService.getNode("companyhome", null, null);
Have a look here:
https://github.com/Alfresco/alfresco-sdk/blob/master/archetypes/alfresco-platform-jar-archetype/src/...
