What causes "ids are null" in flowable/flowable-engine?

Ensure a non-null Set is passed, e.g. deploymentIds(Collections.singleton(deploymentId))

flowable/flowable-engine · error · FlowableIllegalArgumentException

ids are null

Error message

ids are null

What it means

ChannelDefinitionQueryImpl.deploymentIds() throws FlowableIllegalArgumentException when the passed Set<String> of deployment IDs is null. The Flowable query builders validate every filter argument eagerly so that invalid queries fail at construction time with a clear message rather than producing a broken SQL query or a confusing persistence-layer error later.

Solutions

Ensure a non-null Set is passed, e.g. deploymentIds(Collections.singleton(deploymentId))
If no deployment filter is wanted, do not call deploymentIds() at all instead of passing null
Guard the call site: only invoke deploymentIds(ids) when ids != null && !ids.isEmpty()
Initialize the Set with new HashSet<>() before use instead of leaving the variable null

Example fix

// before
Set<String> ids = getConfiguredDeploymentIds(); // may return null
query.deploymentIds(ids);
// after
Set<String> ids = getConfiguredDeploymentIds();
if (ids != null && !ids.isEmpty()) {
    query.deploymentIds(ids);
}

Defensive patterns

Strategy: validation

Validate before calling

if (deploymentIds == null || deploymentIds.isEmpty()) {
    throw new IllegalArgumentException("deploymentIds must be a non-empty set");
}
query.deploymentIds(deploymentIds);

Type guard

boolean hasDeploymentIds(Set<String> ids) {
    return ids != null && !ids.isEmpty();
}

Try / catch

try {
    query.deploymentIds(ids);
} catch (FlowableIllegalArgumentException e) {
    logger.warn("Invalid deploymentIds filter: {}", e.getMessage());
    // proceed with an unfiltered query or rethrow as a client error
}

Prevention

Never pass null to query filter methods; omit the filter call instead
Initialize Set fields eagerly (new HashSet<>()) so they are never null
Use Collections.singleton(id) when filtering on a single deployment
Validate query inputs at the API boundary before building Flowable queries

When it happens

Trigger: Calling channelDefinitionQuery().deploymentIds(null) directly, or passing a Set<String> variable that was never initialized (e.g. a method parameter or a collected set that came back null from another API).

Common situations: Building the query from configuration/properties where deployment IDs were not configured; refactoring code that used deploymentId(String) into a set and forgetting initialization; passing a nullable variable returned by another service.

Related errors

AI-assisted analysis of flowable/flowable-engine@d6d39ce1c6 (2026-09-11). Data as JSON: /api/errors/2c264e143ea17709. Report an issue: GitHub.

Appendix: source

Thrown at modules/flowable-event-registry/src/main/java/org/flowable/eventregistry/impl/ChannelDefinitionQueryImpl.java:155

            throw new FlowableIllegalArgumentException("nameLikeIgnoreCase is null");
        }
        this.nameLikeIgnoreCase = nameLikeIgnoreCase;
        return this;
    }

    @Override
    public ChannelDefinitionQueryImpl deploymentId(String deploymentId) {
        if (deploymentId == null) {
            throw new FlowableIllegalArgumentException("id is null");
        }
        this.deploymentId = deploymentId;
        return this;
    }

    @Override
    public ChannelDefinitionQueryImpl deploymentIds(Set<String> deploymentIds) {
        if (deploymentIds == null) {
            throw new FlowableIllegalArgumentException("ids are null");
        }
        this.deploymentIds = deploymentIds;
        return this;
    }

    @Override
    public ChannelDefinitionQueryImpl parentDeploymentId(String parentDeploymentId) {
        if (parentDeploymentId == null) {
            throw new FlowableIllegalArgumentException("parentDeploymentId is null");
        }
        this.parentDeploymentId = parentDeploymentId;
        return this;
    }

    @Override
    public ChannelDefinitionQueryImpl channelDefinitionKey(String key) {
        if (key == null) {
            throw new FlowableIllegalArgumentException("key is null");

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