flowable/flowable-engine · error · FlowableIllegalArgumentException

caseInstanceId is null

Error message

caseInstanceId is null

What it means

RemoveVariableCmd removes a single variable from a CMMN case instance. It validates its inputs first and throws FlowableIllegalArgumentException when caseInstanceId is null, because removing a variable requires a target case instance.

Solutions

1. Ensure caseInstanceId is non-null before invoking; fail fast at the caller
2. Load the case instance first and use the returned entity's id
3. Add an explicit null guard or Objects.requireNonNull with a clear message
4. If the id comes from a request, validate it as required input

Example fix

// before
cmmnRuntimeService.removeVariable(caseInstanceId, variableName); // caseInstanceId may be null
// after
Objects.requireNonNull(caseInstanceId, "caseInstanceId must not be null");
cmmnRuntimeService.removeVariable(caseInstanceId, variableName);

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

try { cmmnRuntimeService.removeVariable(id, name); } catch (FlowableIllegalArgumentException e) { log.error("Invalid input: {}", e.getMessage()); }

When it happens

Trigger: Passing null as the caseInstanceId argument to the remove-variable command / RuntimeService API, typically when an upstream lookup returned null and the result was forwarded unchecked.

Common situations: caseInstance singleResult() returned null (not found) and code did caseInstance.getId() style chains with nullable ids; optional request parameters bound to null in REST controllers.

Related errors

• caseInstanceId is null
• caseInstanceId is null
• caseInstanceId is null
• caseInstanceId is null
• caseInstanceId is null

AI-assisted analysis of flowable/flowable-engine@d6d39ce1c6 (2026-09-11). Data as JSON: /api/errors/d6240c22c89abf8c. Report an issue: GitHub.

Appendix: source

Thrown at modules/flowable-cmmn-engine/src/main/java/org/flowable/cmmn/engine/impl/cmd/RemoveVariableCmd.java:38

import org.flowable.common.engine.impl.interceptor.CommandContext;

/**
 * @author Joram Barrez
 */
public class RemoveVariableCmd implements Command<Void> {
    
    protected String caseInstanceId;
    protected String variableName;
    
    public RemoveVariableCmd(String caseInstanceId, String variableName) {
        this.caseInstanceId = caseInstanceId;
        this.variableName = variableName;
    }
    
    @Override
    public Void execute(CommandContext commandContext) {
        if (caseInstanceId == null) {
            throw new FlowableIllegalArgumentException("caseInstanceId is null");
        }
        if (variableName == null) {
            throw new FlowableIllegalArgumentException("variableName is null");
        }
     
        CaseInstanceEntity caseInstanceEntity = CommandContextUtil.getCaseInstanceEntityManager(commandContext).findById(caseInstanceId);
        if (caseInstanceEntity == null) {
            throw new FlowableObjectNotFoundException("No case instance found for id " + caseInstanceId, CaseInstanceEntity.class);
        }
        caseInstanceEntity.removeVariable(variableName);
        
        return null;
    }

}

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