flowable/flowable-engine · error · FlowableIllegalArgumentException

A 'maxInstanceCount' on a repetition rule with value '0' is

Error message

A 'maxInstanceCount' on a repetition rule with value '0' is not allowed, either set it to '-1' or 'unlimited' or any other positive value..

What it means

A repetition rule's maxInstanceCount attribute may be '-1' (unlimited), 'unlimited', or any positive integer, but 0 is invalid because a plan item could never be repeated. Flowable rejects it during CMMN XML conversion with this FlowableIllegalArgumentException.

Source

Thrown at modules/flowable-cmmn-converter/src/main/java/org/flowable/cmmn/converter/RepetitionRuleXmlConverter.java:63

            repetitionRule.setRepetitionCounterVariableName(xtr.getAttributeValue(CmmnXmlConstants.FLOWABLE_EXTENSIONS_NAMESPACE, 
                    CmmnXmlConstants.ATTRIBUTE_REPETITION_COUNTER_VARIABLE_NAME));
            
            
            String ignoreRepetitionCounterVariableValue = xtr.getAttributeValue(CmmnXmlConstants.FLOWABLE_EXTENSIONS_NAMESPACE, CmmnXmlConstants.ATTRIBUTE_IGNORE_REPETITION_COUNTER_VARIABLE);
            if ("true".equalsIgnoreCase(ignoreRepetitionCounterVariableValue)) {
                repetitionRule.setIgnoreRepetitionCounterVariable(true);
            }

            String maxInstanceCountValue = xtr.getAttributeValue(CmmnXmlConstants.FLOWABLE_EXTENSIONS_NAMESPACE, CmmnXmlConstants.ATTRIBUTE_REPETITION_MAX_INSTANCE_COUNT_NAME);
            if (maxInstanceCountValue == null) {
                repetitionRule.setMaxInstanceCount(null);
            } else {
                if (RepetitionRule.MAX_INSTANCE_COUNT_UNLIMITED_VALUE.equals(maxInstanceCountValue)) {
                    repetitionRule.setMaxInstanceCount(RepetitionRule.MAX_INSTANCE_COUNT_UNLIMITED);
                } else {
                    int maxInstanceCount = Integer.parseInt(maxInstanceCountValue);
                    if (maxInstanceCount == 0) {
                        throw new FlowableIllegalArgumentException("A 'maxInstanceCount' on a repetition rule with value '0' is not allowed, either set it to '-1' or 'unlimited' or any other positive value..");
                    }
                    repetitionRule.setMaxInstanceCount(maxInstanceCount);
                }
            }

            repetitionRule.setCollectionVariableName(xtr.getAttributeValue(CmmnXmlConstants.FLOWABLE_EXTENSIONS_NAMESPACE,
                CmmnXmlConstants.ATTRIBUTE_REPETITION_COLLECTION_VARIABLE_NAME));

            repetitionRule.setElementVariableName(xtr.getAttributeValue(CmmnXmlConstants.FLOWABLE_EXTENSIONS_NAMESPACE,
                CmmnXmlConstants.ATTRIBUTE_REPETITION_ELEMENT_VARIABLE_NAME));

            repetitionRule.setElementIndexVariableName(xtr.getAttributeValue(CmmnXmlConstants.FLOWABLE_EXTENSIONS_NAMESPACE,
                CmmnXmlConstants.ATTRIBUTE_REPETITION_ELEMENT_INDEX_VARIABLE_NAME));

            planItemControl.setRepetitionRule(repetitionRule);
            
            return repetitionRule;
        }

View on GitHub (pinned to d6d39ce1c6)

Solutions

1. Change maxInstanceCount to a positive value (e.g. 1, 5) in the CMMN XML/model.
2. Use 'unlimited' (or -1) if repetition should be unbounded.
3. Remove the repetitionRule if no repetition was intended.

Example fix

// before
<flowable:repetitionRule flowable:maxInstanceCount="0" />
// after
<flowable:repetitionRule flowable:maxInstanceCount="3" />

public static boolean isValidMaxInstanceCount(String v) {
    if ("unlimited".equals(v)) return true;
    try { return Integer.parseInt(v) != 0; } catch (NumberFormatException e) { return false; }
}

When it happens

Trigger: Converting CMMN XML where a <repetitionRule> (or its extension attribute) declares maxInstanceCount="0"; the value parses as an integer but equals 0.

Common situations: Modelers setting 'max instances' to 0 thinking it disables repetition; programmatic XML generation defaulting the counter to 0.

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

• There can only be one reactivation listener on a case model,
• Job {jobId} parent is not CMMN case
• Either set the user id or the group id for an identity link,
• There is no correlation parameter with name '${correlationPa
• externalJobId must not be empty

AI-assisted analysis of flowable/flowable-engine@d6d39ce1c6 (2026-09-11). Data as JSON: /api/errors/06db2c7601320264. Report an issue: GitHub.