General Notes on the APIs

Unless specifically stated otherwise, null may not be passed as an argument to a method expecting an object type; nor may it be returned from a method as a value of object type. Generally the Javadoc will mention the circumstances under which null may be used, and what it should indicate.
Some classes are marked final only for performance reasons. Typically such classes will mention this in their Javadoc. If you are writing a module and would like to override such a class, please send us email (or post to the Open APIs list) - we will make sure there are not API reasons for having the class be final, and will unfinalize it for the next core release.