Given the following properties file passed on the command line to a Thorntail hollow jar with --properties file.properties:
There are three new system properties, namely parent.children, parent.children.child1.name and parent.children.child2.name.
Results are undefined and depend on the order in which the properties actually end up being submitted to the ConfigResolutionStrategy instance. If the are submitted in the order above, the result is as expected. However, if they are submitted in reverse order, the value for parent.children ends up overriding the child nodes of parent.children and the end result is that only one new system property is added, namely parent.children.
I have reproduced this in a unit test and fixed the issue. I will submit a pull request for this.