flowable/flowable-engine · error · FlowableIllegalArgumentException

key is null

Error message

key is null

What it means

DmnDeploymentQueryImpl.decisionKey(String) throws FlowableIllegalArgumentException when the key parameter is null. The decision key is a mandatory non-null criterion for filtering deployments by the key of decisions they contain; Flowable validates this at the builder call to avoid generating an invalid query.

Source

Thrown at modules/flowable-dmn-engine/src/main/java/org/flowable/dmn/engine/impl/DmnDeploymentQueryImpl.java:148

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

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

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

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

    // sorting ////////////////////////////////////////////////////////

    @Override
    public DmnDeploymentQuery orderByDeploymentId() {

View on GitHub (pinned to d6d39ce1c6)

Solutions

1. Supply the actual decision key string used in the deployed DMN model
2. Only call decisionKey(...) when the key is known and non-null; otherwise omit the filter
3. Verify the source of the key (config, model, service) returns a value; add an explicit null check with a meaningful error

Example fix

// before
query.decisionKey(dmnModel.getDecisionKey()); // may be null
// after
String key = dmnModel.getDecisionKey();
if (key != null) {
    query.decisionKey(key);
}

if (decisionKey == null || decisionKey.isEmpty()) { throw new IllegalArgumentException("decisionKey required for deployment query"); }

boolean hasDecisionKey(String key) { return key != null && !key.isBlank(); }

try { query.decisionKey(key); } catch (FlowableIllegalArgumentException e) { throw new IllegalStateException("Decision key missing in configuration", e); }

When it happens

Trigger: Calling dmnRepositoryService.createDeploymentQuery().decisionKey(null), typically when the key is looked up from configuration, a decision-table reference, or an upstream service response that returned null.

Common situations: Wiring a DMN decision key from application config that is missing; resolving a decision key from a model or BPMN expression that evaluated to null; renaming decision tables and using a stale lookup that no longer matches.

Related errors

• parentDeploymentId is null
• parentDeploymentIdLike is null
• keyLike is null
• decisionDefinitionId is null
• deploymentId is null

AI-assisted analysis of flowable/flowable-engine@d6d39ce1c6 (2026-09-11). Data as JSON: /api/errors/39b80d1fa78a553b. Report an issue: GitHub.