flowable/flowable-engine · error · FlowableIllegalArgumentException

decisionKey is null

Error message

decisionKey is null

What it means

ExecuteDecisionCmd refuses to run a DMN decision when the decision key on the ExecuteDecisionContext is null. The engine cannot resolve a DmnDefinition without a key, so it fails fast with FlowableIllegalArgumentException instead of a confusing lookup error later. The key is normally set via DmnDecisionService.executeDecision with a decision key or by the calling activity behavior.

Source

Thrown at modules/flowable-dmn-engine/src/main/java/org/flowable/dmn/engine/impl/cmd/ExecuteDecisionCmd.java:59

    public ExecuteDecisionCmd(String decisionKey, String parentDeploymentId, Map<String, Object> variables) {
        this(decisionKey, variables);
        executeDecisionContext.setParentDeploymentId(parentDeploymentId);
    }

    public ExecuteDecisionCmd(String decisionKey, String parentDeploymentId, Map<String, Object> variables, String tenantId) {
        this(decisionKey, parentDeploymentId, variables);
        executeDecisionContext.setTenantId(tenantId);
    }

    public ExecuteDecisionCmd(ExecuteDecisionContext executeDecisionContext) {
        super(executeDecisionContext);
    }

    @Override
    public Void execute(CommandContext commandContext) {
        if (executeDecisionContext.getDecisionKey() == null) {
            throw new FlowableIllegalArgumentException("decisionKey is null");
        }

        DmnDefinition definition = resolveDefinition();

        execute(commandContext, definition);

        return null;
    }

}

View on GitHub (pinned to d6d39ce1c6)

Solutions

1. Set the decision key explicitly: dmnEngine.getRuleServices().getDmnDecisionService().executeDecision("myDecisionKey", variables)
2. If the key comes from a variable/property, check it is non-null before invoking the engine and fail with a clear application-level message
3. Verify the ExecuteDecisionContext/ExecuteDecisionBuilder construction includes executeDecisionContext.setDecisionKey(...) or .decisionKey(...) before execute()

Example fix

// before
String key = config.getDecisionKey(); // may be null
decisionService.executeDecision(key, vars);
// after
String key = config.getDecisionKey();
if (key == null || key.isEmpty()) {
    throw new IllegalStateException("DMN decision key not configured");
}
decisionService.executeDecision(key, vars);

if (decisionKey == null || decisionKey.isEmpty()) throw new IllegalArgumentException("decisionKey must be set before executing a decision");

try { decisionService.executeDecision(key, vars); } catch (FlowableIllegalArgumentException e) { if (e.getMessage().contains("decisionKey is null")) { throw new ConfigurationException("DMN decision key not configured", e); } throw e; }

When it happens

Trigger: Calling DmnEngine/DmnRuleServices.executeDecision(...) or building an ExecuteDecisionContext (via ExecuteDecisionBuilder) without ever calling decisionKey(String) — e.g. key variable itself null, or the key comes from an unset process/flow variable.

Common situations: Spring/XML config where the decision key is injected from a property that is missing or empty-null; dynamic keys resolved from a process variable that was never set; refactor renaming the builder method so the key assignment was dropped.

Related errors

• decisionKey is null
• decisionKey is null
• The decision table id is mandatory, but '<decisionTableId>'
• deploymentId is null
• resourceName is null

AI-assisted analysis of flowable/flowable-engine@d6d39ce1c6 (2026-09-11). Data as JSON: /api/errors/5dedc62ba484f6fc. Report an issue: GitHub.