???
How did Wolverine get his adamantium back at the end of the credit Scene of "The Wolverine"?
Well, he never lost it.
The Silver Samurai cut off his adamantium claws. Because of Wolverine's healing factor the claws grew back, but since the adamantium is not a natural part of his body, they grew back as bone claws. Wolverine can't regenerate the adamantium parts of his body!
So in the post credit scene of the Wolverine, he was without adamantium claws, but still with an adamantium skeleton.
And then, by some way we don't know, he also got the adamantium for his claws back at some point during the next eight years, since he has adamantium claws in the future scenes of DOFP.
well i knew all that, but we still don't know how he has his adimantium claws in days of future past. i didn't realize that eight years passed from the end of the wolverine to days of future past, but it seemed like xavier and magento just realigned themselves with wolverine.