flowable/flowable-engine · error · ActivitiException

No outgoing sequence flow of the exclusive gateway

Error message

No outgoing sequence flow of the exclusive gateway '${activityId}' could be selected for continuing the process

What it means

ExclusiveGatewayActivityBehavior.leave() throws this ActivitiException when no outgoing sequence flow's condition evaluates true and the gateway has no default flow at all. The engine cannot decide where to continue, so instead of guessing it fails with the gateway's activity id.

Solutions

  1. Add a default sequence flow to the gateway so there is always a fallback route
  2. Fix the conditions and/or ensure the required variables are set before the gateway
  3. Ensure exactly one condition is unconditional-true or restructure with a condition that always matches
  4. Inspect the process variables at the gateway (e.g. via TaskService/history) to see why all conditions fail

Example fix

// before
<exclusiveGateway id="gw"/>
// after
<exclusiveGateway id="gw" default="fallback"/>
<sequenceFlow id="fallback" sourceRef="gw" targetRef="defaultTask"/>
Defensive patterns

Strategy: validation

Validate before calling

// Before the gateway: guarantee the deciding variables exist
if (variables.get("decisionVar") == null) throw new IllegalStateException("decisionVar missing before exclusive gateway");

Try / catch

try { runtimeService.startProcessInstanceByKey(key, vars); }
catch (ActivitiException e) { if (e.getMessage().contains("No outgoing sequence flow of the exclusive gateway")) { logMissingVars(vars); } throw e; }

Prevention

When it happens

Trigger: Execution reaches an exclusive gateway where every outgoing conditionExpression evaluates false and no default attribute is configured.

Common situations: Conditions depend on process variables that are absent or of the wrong type at runtime; exclusive gateways added after process refactor without a fallback path.

Understand the failure class

Background: 'Could not be found', 'does not exist', 'not found in database': the resource-not-found family when an ID, slug, key, or URI lookup comes back empty — this error's family across 20 libraries.

Related errors

AI-assisted analysis of flowable/flowable-engine@d6d39ce1c6 (2026-09-11). Data as JSON: /api/errors/d72bbe9151149be2. Report an issue: GitHub.

Appendix: source

Thrown at modules/flowable5-engine/src/main/java/org/activiti/engine/impl/bpmn/behavior/ExclusiveGatewayActivityBehavior.java:87

            } else if (SkipExpressionUtil.shouldSkipFlowElement(execution, skipExpression)) {
                outgoingSeqFlow = seqFlow;
            }
        }

        if (outgoingSeqFlow != null) {
            execution.take(outgoingSeqFlow);
        } else {

            if (defaultSequenceFlow != null) {
                PvmTransition defaultTransition = execution.getActivity().findOutgoingTransition(defaultSequenceFlow);
                if (defaultTransition != null) {
                    execution.take(defaultTransition);
                } else {
                    throw new ActivitiException("Default sequence flow '" + defaultSequenceFlow + "' not found");
                }
            } else {
                // No sequence flow could be found, not even a default one
                throw new ActivitiException("No outgoing sequence flow of the exclusive gateway '"
                        + execution.getActivity().getId() + "' could be selected for continuing the process");
            }
        }
    }

}

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