The files for this sample are located in the samples/proxies directory of the Kodo installation. This sample demonstrates custom second class object proxies for mutable persistent fields not directly supported by JDO.
CustomSet is a custom extension of java.util.Set with some extra methods.
CustomStringContainer is a mutable object that holds an internal string. We use this object as a second class object, not a first class object.
The CustomProxies class is a persistence-capable class that uses each of the custom proxies above. The CustomProxiesMain and is a simple driver program for showing that the custom proxies work.