is it a must to use kodo jdo if want to integrate with spring? from my understanding kodo is not free. any free implementation of jdo with spring? any such demo come with source code?
Out of date Spring no longer supports JDO
Spring JDO support should be able to work with any implementation that is compliant to the JDO spec.
For example, here is a tutorial for using the open source JPox JDO implementation with Spring.