flowable/flowable-engine · error · FlowableIllegalArgumentException

Case instance id is null

Error message

Case instance id is null

What it means

FlowableIllegalArgumentException thrown in AbstractNeedsCaseInstanceCmd.execute when the caseInstanceId field is null. The abstract command validates its required id argument before any database lookup, since a null id can never resolve. Any concrete command extending this class (e.g. changing case state, completing a form) inherits this guard.

Source

Thrown at modules/flowable-cmmn-engine/src/main/java/org/flowable/cmmn/engine/impl/cmd/AbstractNeedsCaseInstanceCmd.java:39

import org.flowable.common.engine.api.FlowableObjectNotFoundException;
import org.flowable.common.engine.impl.interceptor.Command;
import org.flowable.common.engine.impl.interceptor.CommandContext;

/**
 * @author Joram Barrez
 */
public abstract class AbstractNeedsCaseInstanceCmd implements Command<Void>, Serializable {
    
    protected String caseInstanceId;

    public AbstractNeedsCaseInstanceCmd(String caseInstanceId) {
        this.caseInstanceId = caseInstanceId;
    }

    @Override
    public Void execute(CommandContext commandContext) {
        if (caseInstanceId == null) {
            throw new FlowableIllegalArgumentException("Case instance id is null");
        }
        
        CmmnEngineConfiguration cmmnEngineConfiguration = CommandContextUtil.getCmmnEngineConfiguration(commandContext);
        CaseInstanceEntity caseInstanceEntity = cmmnEngineConfiguration.getCaseInstanceEntityManager().findById(caseInstanceId);
        if (caseInstanceEntity == null) {
            throw new FlowableObjectNotFoundException("Cannot find case instance for id " + caseInstanceId, CaseInstanceEntity.class);
        }
        
        internalExecute(commandContext, caseInstanceEntity);
        return null;
    }
    
    protected abstract void internalExecute(CommandContext commandContext, CaseInstanceEntity caseInstanceEntity);
   
}

View on GitHub (pinned to d6d39ce1c6)

Solutions

1. Validate the caseInstanceId at the caller level before invoking the CMMN runtime/task service API
2. Log and reject requests that lack the case instance id parameter in your REST/controller layer
3. Check the code path that produced the id (e.g. a previous query result) for null returns
4. Use the correct constructor/builder overload that sets caseInstanceId

Example fix

// before
cmmnRuntimeService.caseInstanceStateChange(caseInstanceId, CaseInstanceState.TERMINATED); // caseInstanceId may be null
// after
if (caseInstanceId == null || caseInstanceId.isBlank()) {
    throw new IllegalArgumentException("caseInstanceId must be provided");
}
cmmnRuntimeService.caseInstanceStateChange(caseInstanceId, CaseInstanceState.TERMINATED);

if (caseInstanceId == null || caseInstanceId.isBlank()) throw new IllegalArgumentException("caseInstanceId is required");

boolean hasCaseInstanceId(String id) { return id != null && !id.isBlank(); }

try { cmmnRuntimeService.caseInstanceStateChange(id, state); }
catch (FlowableIllegalArgumentException e) { log.error("Missing/invalid caseInstanceId: {}", e.getMessage()); }

When it happens

Trigger: Calling a CMMN API such as runtimeService.trigger/case-state commands or task form commands with a null caseInstanceId argument; constructing the command object without setting the id; passing a variable that was never populated (e.g. missing request parameter mapped into the call).

Common situations: REST/HTTP layer where the caseInstanceId path/query parameter was absent and the null propagated into the service call; batch jobs processing lists where an entry lacks the id; misuse of a builder/constructor overload omitting the id.

Related errors

• caseInstanceId is null
• Cannot find case instance for id ${caseInstanceId}
• Plan item instance id is null
• taskId is null
• Cannot find case instance with id

AI-assisted analysis of flowable/flowable-engine@d6d39ce1c6 (2026-09-11). Data as JSON: /api/errors/b08df34b310bdc05. Report an issue: GitHub.