FULL PRODUCT VERSION :
java version "1.8.0_66"
Java(TM) SE Runtime Environment (build 1.8.0_66-b18)
Java HotSpot(TM) 64-Bit Server VM (build 25.66-b18, mixed mode)

A DESCRIPTION OF THE PROBLEM :
java.time.Duration.toNanos() and toMillis() throw an ArithmeticException on an intermediate calculation when the duration is very close to, but greater than Long.MIN_VALUE nanoseconds or milliseconds, respectively.

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Duration.ofNanos(Long.MIN_VALUE).toNanos();

Duration.ofMillis(Long.MIN_VALUE).toMillis();


EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
Expected result from each statement is Long.MIN_VALUE.
ACTUAL -
Both the statements throw ArithmeticException.

REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
public class Bug {
    public static void main(String[] args) {
        // uncomment following line for toNanos() bug
        // Duration.ofNanos(Long.MIN_VALUE).toNanos();
        Duration.ofMillis(Long.MIN_VALUE).toMillis();
    }
}

---------- END SOURCE ----------

CUSTOMER SUBMITTED WORKAROUND :
The following implementations of toNanos() and toMillis() fix the problem:

    public long toMillis() {
        long millis;
        if (isNegative()) {
            millis = Math.multiplyExact(seconds + 1, 1000);
            millis = Math.addExact(millis, nanos / 1000_000 - 1000);
        }
        else {
            millis = Math.multiplyExact(seconds, 1000);
            millis = Math.addExact(millis, nanos / 1000_000);
        }
        return millis;
    }

    public long toNanos() {
        long totalNanos;
        if (isNegative()) {
            totalNanos = Math.multiplyExact(seconds() + 1, NANOS_PER_SECOND);
            totalNanos = Math.addExact(totalNanos, nanos - NANOS_PER_SECOND);
        }
        else {
            totalNanos = Math.multiplyExact(seconds, NANOS_PER_SECOND);
            totalNanos = Math.addExact(totalNanos, nanos);
        }
        return totalNanos;
    }