karatelabs/karate · error · IllegalArgumentException

pauseMillis cannot be negative

Error message

pauseMillis cannot be negative

What it means

Record constructor invariant for MethodPause: a pause duration only makes sense as zero or positive milliseconds. Fires when a negative pauseMillis is passed to the compact constructor; pass 0 or a positive value.

Solutions

1. Use 0 or a positive value for pauseMillis
2. Clamp computed values: Math.max(0, computedPause)
3. Fix the min/max order in any randomization code (e.g. use between(min, max) with min <= max)

Example fix

// before
long pause = target - current; // can be negative
new MethodPause("GET", (int) pause);
// after
long pause = Math.max(0, target - current);
new MethodPause("GET", (int) pause);

if (pauseMillis < 0) throw new IllegalArgumentException("pauseMillis must be >= 0");
new MethodPause(method, pauseMillis);

try { return new MethodPause(method, pauseMillis); } catch (IllegalArgumentException e) { log.warn("rejecting negative pause {}: using 0", pauseMillis); return new MethodPause(method, 0); }

When it happens

Trigger: new MethodPause("GET", -100) — usually from arithmetic like (target - current) that went negative, or a config value entered as a negative number, or subtracting timestamps in the wrong order.

Common situations: Computing randomized pauses where a max below the min yields a negative delta; mis-typed config values in pause tuning; timezone/clock-order bugs when deriving pauses from measured times.

Related errors

• method cannot be null or blank
• pattern cannot be null or blank
• cannot replace root path $
• configure logging.mask: unknown key
• could not build the pooled client's SSL context

AI-assisted analysis of karatelabs/karate@a22eb90246 (2026-09-12). Data as JSON: /api/errors/8532085aadf34b4e. Report an issue: GitHub.

Appendix: source

Thrown at karate-gatling/src/main/java/io/karatelabs/gatling/MethodPause.java:40

 * THE SOFTWARE.
 */
package io.karatelabs.gatling;

/**
 * Represents a pause duration for a specific HTTP method.
 * Used with URI patterns to define method-specific pauses after requests.
 *
 * @param method the HTTP method (GET, POST, etc.)
 * @param pauseMillis the pause duration in milliseconds
 */
public record MethodPause(String method, int pauseMillis) {

    public MethodPause {
        if (method == null || method.isBlank()) {
            throw new IllegalArgumentException("method cannot be null or blank");
        }
        if (pauseMillis < 0) {
            throw new IllegalArgumentException("pauseMillis cannot be negative");
        }
        method = method.toUpperCase();
    }

}

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