Closing ObjectOutputStream before calling toByteArray on the underlying ByteArrayOutputStream

[emopers]

When an ObjectOutputStream instance wraps an underlying ByteArrayOutputStream instance,
it is recommended to flush or close the ObjectOutputStream before invoking the underlying instances's toByteArray().
Although in these cases this is not strictly necessary because the
writeObject method is invoked right before toByteArray, and writeObject
internally calls flush/drain. However, it is a good practice to call
flush/close explicitly as mentioned for example here.
This pull request flips the order of close and toytBeArray methods.
While there are seemingly many changes, they're all just copies of
the same change. Please let me know if you want me to extract the
common code into one helper method.