flowable/flowable-engine · error · FlowableIllegalArgumentException

Can only complete a case instance which is marked as…

Error message

Can only complete a case instance which is marked as completeable. Check if there are active plan item instances.

What it means

CompleteCaseInstanceCmd only completes a case instance whose state is marked completable — meaning the case plan has no active plan item instances blocking completion. If caseInstanceEntity.isCompletable() is false, Flowable throws FlowableIllegalArgumentException instructing you to check for active plan item instances.

Solutions

Terminate/complete all active plan item instances (tasks, stages) first, then call completeCaseInstance.
If the case should be abandoned regardless, use cmmnRuntimeService.terminateCaseInstance(caseInstanceId) instead.
Query plan items first to confirm none active: cmmnRuntimeService.createPlanItemInstanceQuery().caseInstanceId(id).stateActive().count() == 0.
If you control the model, ensure the plan completes automatically (e.g. required/completion rules) so the instance reaches completable state.

Example fix

// before
cmmnRuntimeService.completeCaseInstance(caseInstanceId); // may throw if active plan items exist

// after
long active = cmmnRuntimeService.createPlanItemInstanceQuery()
    .caseInstanceId(caseInstanceId).stateActive().count();
if (active > 0) {
    cmmnRuntimeService.terminateCaseInstance(caseInstanceId);
} else {
    cmmnRuntimeService.completeCaseInstance(caseInstanceId);
}

Defensive patterns

Strategy: try-catch

Validate before calling

long active = cmmnRuntimeService.createPlanItemInstanceQuery().caseInstanceId(id).stateActive().count();
boolean canComplete = active == 0;

Try / catch

try { cmmnRuntimeService.completeCaseInstance(id); } catch (FlowableIllegalArgumentException e) { /* case not completable; terminate instead */ }

Prevention

Check for active plan item instances before completing a case.
Use terminateCaseInstance for abandoning cases with running work.
Model completion rules so cases reach completable state naturally.

When it happens

Trigger: Calling cmmnRuntimeService.completeCaseInstance(caseInstanceId) while the case still has active (not yet completed/terminated) plan item instances, so the case instance is not in the completable state.

Common situations: Attempting programmatic termination of a running case without first ending its active human tasks/stages; assuming completeCaseInstance works like process instance delete; racing with plan items still activating.

Understand the failure class

Background: "Invalid state transition" errors: "status must be X, actually Y", "already rejected/charging/uninstalled", "cannot ... while running" — what they mean when a library rejects your call — this error's family across 31 libraries.

Related errors

AI-assisted analysis of flowable/flowable-engine@d6d39ce1c6 (2026-09-11). Data as JSON: /api/errors/dee99776a8552d8a. Report an issue: GitHub.

Appendix: source

Thrown at modules/flowable-cmmn-engine/src/main/java/org/flowable/cmmn/engine/impl/cmd/CompleteCaseInstanceCmd.java:32

import org.flowable.cmmn.engine.impl.persistence.entity.CaseInstanceEntity;
import org.flowable.cmmn.engine.impl.util.CommandContextUtil;
import org.flowable.common.engine.api.FlowableIllegalArgumentException;
import org.flowable.common.engine.impl.interceptor.CommandContext;

/**
 * @author Joram Barrez
 */
public class CompleteCaseInstanceCmd extends AbstractNeedsCaseInstanceCmd {

    public CompleteCaseInstanceCmd(String caseInstanceId) {
        super(caseInstanceId);
    }
    
    @Override
    protected void internalExecute(CommandContext commandContext, CaseInstanceEntity caseInstanceEntity) {
        if (!caseInstanceEntity.isCompletable()) {
            throw new FlowableIllegalArgumentException("Can only complete a case instance which is marked as completeable. Check if there are active plan item instances.");
        }
        CommandContextUtil.getAgenda(commandContext).planCompleteCaseInstanceOperation(caseInstanceEntity);
    }

}

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