It seems that the correct link should be http://www.oracle.com/technetwork/indexes/samplecode/ (or some specific location under it).
I'll pass this along to the right person in the Fusion Middleware documentation group.
A correction/clarification: There's no "Oracle Identity Management link" on the sample code URL that I mentioned. The writer is checking into this, and will make the appropriate fix at the next opportunity to republish this book. (If there are no suitable Identity Management code samples available, the text that refers to them will be removed from that chapter.)