If I remember the discussions correctly, it is in the sandbox because it is incomplete, is not currently spec compliant, and the javamail api is not well separated from implementing javamail itself, so you would essentially have to implement all of the javamail functionality to make it usable. I could be wrong on this, I haven't looked into these issues myself. I'm sure if you finish it up everyone will be thrilled.
There are also concerns about whether this API can actually be implemented from the specification - there are a lot of concrete classes in the API whose behaviour may not be sufficiently documented. I remember extensive discussions last year on the correctness of "equals" vs. what the RI actually does.
On the other hand, we have to have an implementation of both the JavaMail and Activation APIs and we cannot redistribute Sun's due to licensing restrictions. Perhaps the time as come to finish this work, run it through the CTS and then work with Sun to clarify the Specifications.
Another issue is that the JAXR specification depends on Activation so procuding its spec API will have a dependency issue.
I'd say let's move these back out of the sandbox and get going.
-- Jeremy
