quarkusio/quarkus · error · IllegalArgumentException

Page index must be >= 0 :

Error message

Page index must be >= 0 : 

What it means

Panache's Page represents a pagination request (index + size). The constructor validates that the page index is non-negative; a negative index is meaningless in pagination, so it throws IllegalArgumentException immediately rather than producing an invalid query later.

Source

Thrown at extensions/panache/panache-common/runtime/src/main/java/io/quarkus/panache/common/Page.java:53

     * @throws IllegalArgumentException if the page size is less than or equal to 0
     * @see #ofSize(int)
     */
    public Page(int size) {
        this(0, size);
    }

    /**
     * Builds a page of the given index and size.
     *
     * @param index the page index (0-based)
     * @param size the page size
     * @throws IllegalArgumentException if the page index is less than 0
     * @throws IllegalArgumentException if the page size is less than or equal to 0
     * @see #of(int, int)
     */
    public Page(int index, int size) {
        if (index < 0)
            throw new IllegalArgumentException("Page index must be >= 0 : " + index);
        if (size <= 0)
            throw new IllegalArgumentException("Page size must be > 0 : " + size);
        this.index = index;
        this.size = size;
    }

    /**
     * Builds a page of the given index and size.
     *
     * @param index the page index (0-based)
     * @param size the page size
     * @throws IllegalArgumentException if the page index is less than 0
     * @throws IllegalArgumentException if the page size is less than or equal to 0
     */
    public static Page of(int index, int size) {
        return new Page(index, size);
    }

View on GitHub (pinned to e1c734241f)

Solutions

1. Validate/clamp the page index before constructing: Math.max(0, pageIndex).
2. Return HTTP 400 for negative page parameters instead of letting them reach Panache.
3. Use Page.of(index, size) with sanitized values.

Example fix

// before
Page p = Page.of(Integer.parseInt(request.getParam("page")), 20);
// after
int idx = Math.max(0, Integer.parseInt(request.getParam("page")));
Page p = Page.of(idx, 20);

int idx = /* user input */;
if (idx < 0) throw new BadRequestException("page index must be >= 0");
Page p = Page.of(idx, size);

Page safePage(Integer index, int size) {
    return Page.of(index == null ? 0 : Math.max(0, index), size);
}

try {
    Page p = Page.of(index, size);
} catch (IllegalArgumentException e) {
    throw new BadRequestException("Invalid page index: " + e.getMessage());
}

When it happens

Trigger: Calling new Page(-1, 10), Page.of(-1, 10), or chaining pagination APIs (page(int), page(Page)) that construct a Page with a negative index — often from unvalidated user input like ?page=-1.

Common situations: Passing a request query parameter straight into page() without validation; computing index as currentPage-1 when currentPage is 0; arithmetic underflow from offset math.

Related errors

• Limiting to 0 values is not supported
• Limiting to 0 values is not supported
• Limiting to 0 values is not supported
• Page size must be > 0 :
• Start index must be >= 0:

AI-assisted analysis of quarkusio/quarkus@e1c734241f (2026-09-05). Data as JSON: /api/errors/67b228b6f071be13. Report an issue: GitHub.