I found some issues in FileMailQueue. In
JAMES-1429 the problem in the `init()` method was solved. I think the remaining problems described there could be related to the first of these two:
- in `enQueue()`, the NEXT_DELIVERY date is set into the mail after it has already been written to disk. So after a restart, the mails are put into the queue without taking the NEXT_DELIVERY into account. This would result in delivering them immediately, if I understand correctly.
- in `deQueue()` l.289, the file item is deleted, but the `keyMappings` cache is not updated. This breaks the management methods (clear/flush/browse) and the cache will grow infinitely.
I'll attach a patch for these two.