ReactiveX/RxJava · error · IllegalArgumentException

Integer overflow

Error message

Integer overflow

What it means

Thrown by Streamable.range when the inclusive endpoint start + (count - 1) exceeds Integer.MAX_VALUE. Because the operator emits ints, the range must fit in the int domain; the library casts to long to detect overflow safely and fails fast rather than wrapping.

Source

Thrown at src/main/java/io/reactivex/rxjava4/core/Streamable.java:496

     * @param start the start element
     * @param count the number of elements to emit
     * @return the new {@code Streamable} instance
     * @throws IllegalArgumentException if {@code count} is negative
     */
    @CheckReturnValue
    @NonNull
    static Streamable<Integer> range(int start, int count) {
        if (count < 0) {
            throw new IllegalArgumentException("count >= 0 required but it was " + count);
        } else
        if (count == 0) {
            return empty();
        } else
        if (count == 1) {
            return just(start);
        } else
        if ((long)start + (count - 1) > Integer.MAX_VALUE) {
            throw new IllegalArgumentException("Integer overflow");
        }
        return RxJavaPlugins.onAssembly(new StreamableRange(start, count));
    }

    /**
     * Emits elements from start up to start + count exclusive.
     * @param start the start element
     * @param count the number of elements to emit
     * @return the new {@code Streamable} instance
     * @throws IllegalArgumentException if {@code count} is negative
     */
    @CheckReturnValue
    @NonNull
    static Streamable<Long> rangeLong(long start, long count) {
        if (count < 0) {
            throw new IllegalArgumentException("count >= 0 required but it was " + count);
        }

View on GitHub (pinned to a8ab535614)

Solutions

1. Reduce start and/or count so the inclusive end stays <= Integer.MAX_VALUE.
2. Validate up front: boolean overflow = (long)start + (count - 1) > Integer.MAX_VALUE.
3. Switch to Streamable.rangeLong if you need the long domain.

Example fix

// before
Streamable.range(Integer.MAX_VALUE - 10, 100);

// after
// option A: clamp into the int domain
int start = Integer.MAX_VALUE - 10;
int count = Math.min(100, Integer.MAX_VALUE - start + 1);
Streamable.range(start, count);
// option B: move to the long domain
Streamable.rangeLong((long)Integer.MAX_VALUE - 10, 100L);

if ((long)start + (count - 1) > Integer.MAX_VALUE) {
    count = Integer.MAX_VALUE - start + 1;
}

try {
    return Streamable.range(start, count);
} catch (IllegalArgumentException e) {
    return Streamable.rangeLong((long)start, (long)count);
}

When it happens

Trigger: Calling Streamable.range(start, count) where (long)start + (count - 1) > Integer.MAX_VALUE. Happens with high positive start values plus a large count.

Common situations: Generating ranges that cross the top of the int domain; counters near Integer.MAX_VALUE; unvalidated computed ranges.

Related errors

• Integer overflow
• Overflow! start + count is bigger than Long.MAX_VALUE
• Overflow! start + count is bigger than Long.MAX_VALUE
• Overflow! start + count is bigger than Long.MAX_VALUE
• count >= 0 required but it was {}

AI-assisted analysis of ReactiveX/RxJava@a8ab535614 (2026-08-13). Data as JSON: /api/errors/f6d002102c0842c9. Report an issue: GitHub.