Project Wonder JavaDoc
Apple Printed WebObjects Documentation:
Apple is no longer updating this documentation and considers it to be "Legacy" because of the outdated UI of the developer tools used in the examples. While the UI is outdated, this documentation is still accurate with regards to the frameworks themselves.
Apple's documentation is available for several versions of WebObjects on the Apple Developer Website. Since this URL tends to change here's a local cache of many of the most useful documents: