Sri Krishn in his virat swarup
It is said that Jara mistakenly hit an arrow in sri Krishn's feet.
Jara was hunter( Baheliya) . Sri krishn himself chosen to be killed by Jara.
Some reasons are:-
1 . The Jara was the Bali ( Ramayan) who was hit by Sri Ram mistakenly behind the bush ,so sri Krishn was also hit by same process in present birth
2 .. It is also that it was Gandhari curse, because of all sons were killed by deceiving of Sri Krishn in the Mahabharata War.
In my opinion..
Sri krishn is (supreme)Ishwar himself. It was only a play which was played by Sri Krishn to depart from this world.
How a Ishwar can die? Who has that much of capacity and power to destroy Sri Krishn body except himself?
He returned his dham with his own golden, divine and supernatural form.