Why are there no short-circuiting compound assignment operators `&&=` and `||=`?

[Brian Goetz]

> https://stackoverflow.com/q/2324549/ shows that there is interest in having these operators and there
> are no clear arguments why they don't exist yet.
> The question is therefore: Has the JDK team discussed adding these operators in the past and if so
> what where the reasons against adding them?

I'm not aware of any specific discussion on this particular issue, but 
if someone were to propose it, the answer would likely be: it's not an 
unreasonable request, but it doesn't carry its weight.

"Carrying its weight" needs to be judged by its costs and benefits, and 
by its cost-benefit ratio relative to other candidate features.

I think you are implicitly assuming (by the phrase "there is interest") 
that the cost is near zero and the benefit is greater than zero, so it 
seems an obvious win.  But this belies an incorrect understanding of 
cost; a feature like this affects the language spec, the implementation, 
the JCK, and every IDE and Java textbook. There are no trivial language 
features.  And the benefit, while nonzero, is pretty small.

Secondarily, there are infinitely many features we _could_ do, but we 
only have capacity to do a handful every few years (and users have a 
limited capacity to absorb new features.)  So we have to be very careful 
as to which we pick, as each feature (even a trivial-seeming one) 
consumes some of this budget, and invariably takes it away from others.  
It's not "why not this feature", but "what other features will we not do 
(or delay) so we can do this one, and is that a good trade?"  And I 
can't really imagine this being a good trade against anything else we're 
working on.

So, it clears the bar of "not a terrible idea" (which is already pretty 
good, a lot of feature requests don't even clear that), but seems 
unlikely to ever clear the bar of "a better use of our evolution budget 
than anything else."