Duration.MAX_VALUE

[Pavel Rappo]

This is useful; thanks. It would be good to see more of your data.

My use case is also duration which practically means **forever**. I
pass it to methods that accept timeouts, and expect these methods to
correctly interpret it.

One example of a practical interpretation is
java.util.concurrent.TimeUnit.convert(Duration). This method never
overflows; instead, it caps at Long.MAX_VALUE nanoseconds, which is
roughly 292 years.

Would I be okay, if the proposed duration didn't reflect **forever**
but instead reflected **long enough**? I think so. But it still
somehow feels wrong to make it less than maximum representable value.

Personally, I'm not interested in calendar arithmetic, that is, in
adding or subtracting durations. Others might be, and that's okay and
needs to be factored in. For better or worse, java.time made a choice
to be unforgiving in regard to overflow and is very upfront about it.
It's not only proposed Duration.MAX. The same thing happens if you try
this

    Instant.MAX.toEpochMilli()

I guess my point is that doing calendar arithmetic on an unknown value
is probably wrong. Doing it on a known huge/edge-case value is surely
wrong. So back to your data. I would be interested to see what
triggers overflows for your Durations.MAX.

On Wed, Sep 3, 2025 at 8:45 PM Kurt Alfred Kluever <kak at google.com> wrote:
>
> Hi all,
>
> Internally at Google, we've had a Durations.MAX constant exposed for the past 7 years. It now has about 700 usages across our depot, which I can try to categorize (at a future date).
>
> While I haven't performed that analysis yet, I think exposing this constant was a bit of a mistake. People seem to want to use MAX to mean "forever" (often in regards to an RPC deadline). This works fine as long as every single layer that touches the deadline is very careful about overflow. The only reasonable thing you can do with MAX is compareTo() and equals(). Attempting to do any simple math operation (e.g., now+deadline) is going to explode. Additionally, decomposing Duration.MAX explodes for any sub-second precision (e.g., toMillis()).
>
> As we dug into this, another proposal came up which was something like Durations.VERY_LONG. This duration would be longer than any reasonable finite duration but not long enough to cause an overflow when added to any reasonable time. E.g., a million years would probably satisfy both criteria. This would mean math operations and decompositions won't explode (well, microseconds and nanoseconds still would), and it could safely be used as a relative timeout.
>
> As I mentioned above, I'd be happy to try to categorize a sample of our 700 existing usages if folks think that would be useful for this proposal.
>
> Thanks,
>
> -Kurt Alfred Kluever (on behalf of Google's Java and Kotlin Ecosystem team)
>
> On Wed, Sep 3, 2025 at 1:53 PM Pavel Rappo <pavel.rappo at gmail.com> wrote:
>>
>> If I understood you correctly, you think we should also add
>> Duration.MIN. If so, what use case do you envision for it? Or we add
>> if purely for symmetry with Instant?
>>
>> On Wed, Sep 3, 2025 at 6:43 PM Pavel Rappo <pavel.rappo at gmail.com> wrote:
>> >
>> > On Wed, Sep 3, 2025 at 6:06 PM Stephen Colebourne <scolebourne at joda.org> wrote:
>> > >
>> > > Hmm, yes. Not sure why that didn't get added in Java 8!
>> > > The constants would be MAX/MIN as per classes like Instant.
>> > > Stephen
>> >
>> > I thought that naming could be tricky :) The public constant
>> > Duration.ZERO and the public method isZero() are already there.
>> > However, it does not preclude us from naming a new constant MAX.
>
>
>
> --
> kak