"Bean” can sound like “been,” and there’s a pun:

QL What do you call a retired vegetable?
A: A has-bean.

“What do you call an obsolete Java Bean? A “has"-Bean" was posted to the newsgroup comp.lang.java.programmer on June 6, 1999. “What do you call a long, thin, green vegetable that’s seen better days? A has-bean” was posted to the newsgroup alt.humor on July 25, 2003.

“What do you call a retired vegetable? A has-bean” has been cited in print since at least 2006.


Google Groups: comp.lang.java.programmer
Visual J++ 6.0. What is it good for?
Dan Hinojosa
6/6/99
(...)
> What do you call an obsolete Java Bean?
>
> A “has"-Bean

Google Groups: alt.support.childfree
Bastards Listen Up
Lurker Above
1/29/02
(...)
Q: what do you call a retired coffee shop barista?
A: a has-bean

Google Groups: alt.humor
Puns of the Weak 07-25-03
Stan Kegel
7/25/03
(...)
What do you call a long, thin, green vegetable that?s seen better days?
A has-bean. (Cynthia MacGregor)

Jamie Oliver—Forum
shammrok
Thu 09 Nov 06 2:39am
(...)
What do you call a retired vegetable?
- A has-bean

Google Books
101 Short and Hilarious Jokes for Kids:
Jokes They’ll Tell Again and Again
By Scott Allen
Delabarre Publishing at Smashwords
2010
Pg. ?:
What do you call an elderly vegetable?
A has-bean.

Passy’s World of ICT
FRIDAY, JULY 30, 2010
Fruity Friday Funny
(...)
Q: What do you call a retired vegetable?
A: A has-bean.

Twitter
5adaynz
‏@5adaynz
What do you call a retired vegetable? A has-bean! hehe how is everyone going back at work? Love Fredge xx
3:04 PM - 17 Jan 2011

Secret Seed Society
Top 100 veggie jokes of all time
April 27, 2011
Here’s a growing collection of the top 100 veggie jokes of all time…
(...)
COMMENTS
Evan on August 22, 2011 at 5:46 pm said:
What do you call a retired vegetable?
A has bean!

Twitter
dclapp818
‏@dclapp818
What do you call an elderly vegetable?  A has-bean!
5:06 PM - 23 May 2011