flowable/flowable-engine · error · ActivitiIllegalArgumentException

Provided event type is null

Error message

Provided event type is null

What it means

EventSubscriptionQueryImpl.eventType(String) throws ActivitiIllegalArgumentException when the caller passes a null event type. The Flowable query API validates required filter fields eagerly in the fluent setter so an invalid query fails immediately rather than producing a broken SQL query or empty results at list() time. An event type (e.g. 'signal', 'message') is mandatory to scope the event subscription query.

Solutions

1. Pass a valid event type string, e.g. query.eventType(EventType.SIGNAL.name()) or a concrete literal like 'signal'.
2. Null-check or default the value before calling eventType(): if (type != null) query.eventType(type);
3. If the type comes from config, verify the configuration source is actually loaded and the key exists.
4. Catch ActivitiIllegalArgumentException to surface a clear message to the user instead of an ambiguous failure.

Example fix

// before
String type = props.getProperty("event.type");
EventSubscriptionQuery q = runtimeService.createEventSubscriptionQuery().eventType(type);

// after
String type = props.getProperty("event.type");
if (type == null) {
    throw new ConfigurationException("event.type must be configured");
}
EventSubscriptionQuery q = runtimeService.createEventSubscriptionQuery().eventType(type);

if (eventType == null || eventType.isEmpty()) {
    throw new IllegalArgumentException("eventType must be a non-empty string before calling eventType()");
}
runtimeService.createEventSubscriptionQuery().eventType(eventType);

boolean isValidEventType(String s) { return s != null && !s.isEmpty(); }

try {
    query.eventType(eventType);
} catch (ActivitiIllegalArgumentException e) {
    log.error("Invalid event subscription query: {}", e.getMessage());
    throw new BadRequestException("event type must not be null", e);
}

When it happens

Trigger: Calling eventSubscriptionQuery().eventType(null) — typically eventType(variable) or eventType(someMap.get(key)) where the variable is null or the map lookup missed.

Common situations: Event type stored in configuration/properties that was never loaded; reflection or deserialization building queries from nullable DTO fields; a refactor renamed a constant so the lookup returns null.

Related errors

• Business key is null
• Business status is null
• Case definition category is null
• Case definition id is null
• Case definition ids is null

AI-assisted analysis of flowable/flowable-engine@d6d39ce1c6 (2026-09-11). Data as JSON: /api/errors/3f76dd963572e24a. Report an issue: GitHub.

Appendix: source

Thrown at modules/flowable5-engine/src/main/java/org/activiti/engine/impl/EventSubscriptionQueryImpl.java:89

    public EventSubscriptionQueryImpl processInstanceId(String processInstanceId) {
        if (processInstanceId == null) {
            throw new ActivitiIllegalArgumentException("Provided process instance id is null");
        }
        this.processInstanceId = processInstanceId;
        return this;
    }

    public EventSubscriptionQueryImpl activityId(String activityId) {
        if (activityId == null) {
            throw new ActivitiIllegalArgumentException("Provided activity id is null");
        }
        this.activityId = activityId;
        return this;
    }

    public EventSubscriptionQueryImpl eventType(String eventType) {
        if (eventType == null) {
            throw new ActivitiIllegalArgumentException("Provided event type is null");
        }
        this.eventType = eventType;
        return this;
    }

    public String getTenantId() {
        return tenantId;
    }

    public EventSubscriptionQueryImpl tenantId(String tenantId) {
        this.tenantId = tenantId;
        return this;
    }

    public EventSubscriptionQueryImpl orderByCreated() {
        return orderBy(EventSubscriptionQueryProperty.CREATED);
    }

View on GitHub (pinned to d6d39ce1c6)