flowable/flowable-engine · error · java.text.ParseException

Day of month values must be between 1 and 31

Error message

Day of month values must be between 1 and 31

What it means

CronExpression validates the DAY_OF_MONTH field during parsing in addToSet: the day value and the end of any day range must be between 1 and 31 (the wildcard '*' sentinel and the '?' NO_SPEC sentinel are exempt). Otherwise new CronExpression(String) throws a java.text.ParseException with this message at construction time.

Source

Thrown at modules/flowable-engine-common/src/main/java/org/flowable/common/engine/impl/calendar/CronExpression.java:985

        return i;
    }

    protected void addToSet(int val, int end, int incr, int type) throws ParseException {

        TreeSet<Integer> set = getSet(type);

        if (type == SECOND || type == MINUTE) {
            if ((val < 0 || val > 59 || end > 59) && (val != ALL_SPEC_INT)) {
                throw new ParseException("Minute and Second values must be between 0 and 59", -1);
            }
        } else if (type == HOUR) {
            if ((val < 0 || val > 23 || end > 23) && (val != ALL_SPEC_INT)) {
                throw new ParseException("Hour values must be between 0 and 23", -1);
            }
        } else if (type == DAY_OF_MONTH) {
            if ((val < 1 || val > 31 || end > 31) && (val != ALL_SPEC_INT) && (val != NO_SPEC_INT)) {
                throw new ParseException("Day of month values must be between 1 and 31", -1);
            }
        } else if (type == MONTH) {
            if ((val < 1 || val > 12 || end > 12) && (val != ALL_SPEC_INT)) {
                throw new ParseException("Month values must be between 1 and 12", -1);
            }
        } else if (type == DAY_OF_WEEK) {
            if ((val == 0 || val > 7 || end > 7) && (val != ALL_SPEC_INT) && (val != NO_SPEC_INT)) {
                throw new ParseException("Day-of-Week values must be between 1 and 7", -1);
            }
        }

        if ((incr == 0 || incr == -1) && val != ALL_SPEC_INT) {
            if (val != -1) {
                set.add(val);
            } else {
                set.add(NO_SPEC);
            }

View on GitHub (pinned to d6d39ce1c6)

Solutions

1. Correct the day-of-month token to be in 1-31 (no zero-based indexing).
2. Verify field order in the expression (sec min hour day month dow) — a shifted field often causes out-of-range values.
3. For 'last day of month' use 'L' where supported, or compute the date programmatically instead of day 0/32.
4. Pre-validate with CronExpression.isValidExpression() and reject the configuration at startup.

Example fix

// before
CronExpression expr = new CronExpression("0 0 0 0 * ?"); // day 0 invalid
// after
CronExpression expr = new CronExpression("0 0 0 1 * ?");

if (!CronExpression.isValidExpression(cron)) {
    throw new IllegalArgumentException("Invalid cron: day-of-month must be 1-31 in " + cron);
}
CronExpression expr = new CronExpression(cron);

try {
    CronExpression expr = new CronExpression(cron);
} catch (ParseException e) {
    log.error("Invalid day-of-month in cron '{}'", cron, e);
    throw new ConfigurationException(e);
}

When it happens

Trigger: new CronExpression(cronString) with a day-of-month token of 0, negative, or >31, e.g. '0 0 0 32 * ?' or '0 0 0 0 * ?'. Also a range whose end exceeds 31 such as '0 0 0 30-32 * ?'.

Common situations: Typo'd cron fields in BPMN timeCycle definitions (fields shifted so a month number lands in the day slot); zero-based day generation (0-30 instead of 1-31) when converting from an API that indexes days from 0; 'day 0' meaning 'last day' confusion.

Understand the failure class

Background: "value must be between 0 and 1" / "out of range" / "must not be negative" errors: fixing range-validation failures across open-source libraries — this error's family across 42 libraries.

Related errors

• Hour values must be between 0 and 23
• Month values must be between 1 and 12
• '#' option is not valid here. (pos=
• Unexpected character '<c>' after '/'
• Minute and Second values must be between 0 and 59

AI-assisted analysis of flowable/flowable-engine@d6d39ce1c6 (2026-09-11). Data as JSON: /api/errors/971366d2acfdfaaa. Report an issue: GitHub.