flowable/flowable-engine · error · FlowableIllegalArgumentException

callbackId is null

Error message

callbackId is null

What it means

Flowable throws this FlowableIllegalArgumentException when CaseInstanceQueryImpl.caseInstanceCallbackId(String) is called with a null callbackId. The callback id links a case instance to a callback (e.g. from a process/task); null is not an acceptable filter, so the engine fails fast at query build time.

Solutions

1. Pass the actual non-null callback id
2. Return an empty result / skip the query when the callback id is unknown
3. Check the source entity for a callback id before querying

Example fix

// before
query.caseInstanceCallbackId(callbackId); // throws when callbackId == null
// after
if (callbackId != null) {
    query.caseInstanceCallbackId(callbackId);
}

if (callbackId != null && !callbackId.isBlank()) {
    query.caseInstanceCallbackId(callbackId);
}

boolean hasCallbackId(CaseInstance c) { return c != null && c.getCallbackId() != null; }

try {
    query.caseInstanceCallbackId(callbackId);
} catch (FlowableIllegalArgumentException e) {
    log.warn("No callback id filter applied: {}", e.getMessage());
    return Collections.emptyList();
}

When it happens

Trigger: Calling caseInstanceQuery.caseInstanceCallbackId(null) directly, or forwarding a callbackId read from a related entity/variable that was never set.

Common situations: Correlation lookups between processes and case instances where the callback id variable is absent; passing a payload field that is optional in the incoming request; early-version data (pre-callback support) lacking the field.

Related errors

• Parent id is null
• Provided sub scope id is null
• state is null
• user id is null
• activatedBefore is null

AI-assisted analysis of flowable/flowable-engine@d6d39ce1c6 (2026-09-11). Data as JSON: /api/errors/fece5c7ddd846b59. Report an issue: GitHub.

Appendix: source

Thrown at modules/flowable-cmmn-engine/src/main/java/org/flowable/cmmn/engine/impl/runtime/CaseInstanceQueryImpl.java:635

    }

    @Override
    public CaseInstanceQuery caseInstanceLastReactivatedBy(String userId) {
        if (userId == null) {
            throw new FlowableIllegalArgumentException("user id is null");
        }
        if (inOrStatement) {
            this.currentOrQueryObject.lastReactivatedBy = userId;
        } else {
            this.lastReactivatedBy = userId;
        }
        return this;
    }

    @Override
    public CaseInstanceQuery caseInstanceCallbackId(String callbackId) {
        if (callbackId == null) {
            throw new FlowableIllegalArgumentException("callbackId is null");
        }
        if (inOrStatement) {
            this.currentOrQueryObject.callbackId = callbackId;
        } else {
            this.callbackId = callbackId;
        }
        return this;
    }

    @Override
    public CaseInstanceQuery caseInstanceCallbackIds(Set<String> callbackIds) {
        if (callbackIds == null || callbackIds.isEmpty()) {
            throw new FlowableIllegalArgumentException("callbackIds is null or empty");
        }
        if (inOrStatement) {
            this.currentOrQueryObject.callbackIds = callbackIds;
        } else {
            this.callbackIds = callbackIds;

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