I wanted to use DocumentProperties to temporarily store Date objects using presentation.getDocumentProperties().set(String name, Object value).
Neither documentation nor the signature denies to use arbitrary classes as values.
But in fact, if I set a non-String value, it's just vanished in thin air, since get(String name) return always null.
This might be a bug.
I would expect either a specifically designed signature to allow Strings only or at least documented behavior and raise of an Exception, immediately when set() is called.
It's not the first time I raise such issues, that cause problems later, mostly having no hint to the cause.
And since it's wrapped code, nothing really is able to be done but try/error.
Jens Gehrke, Oracle