alibaba/spring-cloud-alibaba · error · ParseException

Unexpected end of string.

Error message

Unexpected end of string.

What it means

Thrown after a '*' (or leading '/') is consumed and a following '/' is found, but advancing past the '/' runs off the end of the token — i.e. there is no increment value after the slash at all (guard at CronExpression.java:425-426). This differs from error 80, which fires on a leading '/' followed by whitespace; error 81 fires when '*' was already consumed and the trailing '/' has no digit. It is a checked ParseException from the constructor.

Source

Thrown at spring-cloud-alibaba-starters/spring-cloud-starter-alibaba-schedulerx/src/main/java/com/alibaba/cloud/scheduling/schedulerx/util/CronExpression.java:426

		if (c == '*' || c == '/') {
			if (c == '*' && (i + 1) >= s.length()) {
				addToSet(ALL_SPEC_INT, -1, incr, type);
				return i + 1;
			}
			else if (c == '/'
					&& ((i + 1) >= s.length() || s.charAt(i + 1) == ' ' || s
					.charAt(i + 1) == '\t')) {
				throw new ParseException("'/' must be followed by an integer.", i);
			}
			else if (c == '*') {
				i++;
			}
			c = s.charAt(i);
			if (c == '/') { // is an increment specified?
				i++;
				if (i >= s.length()) {
					throw new ParseException("Unexpected end of string.", i);
				}

				incr = getNumericValue(s, i);

				i++;
				if (incr > 10) {
					i++;
				}
				if (incr > 59 && (type == SECOND || type == MINUTE)) {
					throw new ParseException("Increment > 60 : " + incr, i);
				}
				else if (incr > 23 && (type == HOUR)) {
					throw new ParseException("Increment > 24 : " + incr, i);
				}
				else if (incr > 31 && (type == DAY_OF_MONTH)) {
					throw new ParseException("Increment > 31 : " + incr, i);
				}
				else if (incr > 7 && (type == DAY_OF_WEEK)) {

View on GitHub (pinned to 115d590110)

Solutions

1. Add the missing step integer after the trailing '/', e.g. '*/' -> '*/2'.
2. Audit config templates/property placeholders so an empty `${step}` cannot yield a bare '*/'.
3. Use '*' alone if you want 'every' rather than a step.
4. Validate the cron string with the helper below before constructing.

Example fix

// before
new CronExpression("0 0 0 ? * */");
// after
new CronExpression("0 0 0 ? * */2"); // every 2 days-of-week

// Reject tokens that end with a bare '*/'.
static boolean noTrailingBareSlash(String cron) {
    if (cron == null) return true;
    for (String f : cron.trim().split("\\s+")) {
        if (f.endsWith("*/") || f.endsWith("/")) return false;
    }
    return true;
}

try {
    CronExpression cron = new CronExpression(raw);
} catch (ParseException e) {
    throw new IllegalArgumentException("Invalid cron expression: " + raw, e);
}

When it happens

Trigger: Constructing `new CronExpression("0 0 0 ? * */")` where the day-of-week (last) field is '*/' with nothing after the slash. Any field token ending in exactly '*/' with no digits triggers the `i >= s.length()` check at line 425.

Common situations: Truncation of a cron string (e.g. a config value trimmed to `"0 0 0 ? * */"`), or a templated cron where `${step}` was empty producing `*/`. Also from copy-paste where the trailing increment was dropped.

Related errors

• '/' must be followed by an integer.
• Increment > 60 : {}
• Increment > 24 : {}
• Increment > 31 : {}
• Increment > 7 : {}

AI-assisted analysis of alibaba/spring-cloud-alibaba@115d590110 (2026-08-14). Data as JSON: /api/errors/e66497feae3dea32. Report an issue: GitHub.