Futures contracts, like stocks, have no expiration date and can be held for a long time.
You can't. Futures contracts and stocks can always be held in different ways. Every commodity futures contract has an expiration date, and you can't hold a position all the time. A futures contract is an agreement in which the buyer agrees to receive assets at a specific price after a specified time, and the seller agrees to deliver assets at a specific price after a specified time.