flowable/flowable-engine · error · FlowableIllegalArgumentException

caseInstanceId is null

Error message

caseInstanceId is null

What it means

GetCaseVariableInstancesCmd validates that a caseInstanceId was supplied before it looks up the case instance. A null id cannot identify any case, so Flowable throws FlowableIllegalArgumentException immediately. This is a caller contract violation, not an engine-state problem.

Source

Thrown at modules/flowable-cmmn-engine/src/main/java/org/flowable/cmmn/engine/impl/cmd/GetCaseVariableInstancesCmd.java:42

import org.flowable.common.engine.impl.interceptor.CommandContext;
import org.flowable.variable.api.persistence.entity.VariableInstance;

public class GetCaseVariableInstancesCmd implements Command<Map<String, VariableInstance>>, Serializable {

    private static final long serialVersionUID = 1L;
    
    protected String caseInstanceId;

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

    @Override
    public Map<String, VariableInstance> execute(CommandContext commandContext) {

        // Verify existence of execution
        if (caseInstanceId == null) {
            throw new FlowableIllegalArgumentException("caseInstanceId is null");
        }

        CaseInstanceEntity caseInstance = CommandContextUtil.getCaseInstanceEntityManager(commandContext).findById(caseInstanceId);

        if (caseInstance == null) {
            throw new FlowableObjectNotFoundException("case instance " + caseInstanceId + " doesn't exist", CaseInstance.class);
        }

        return caseInstance.getVariableInstances();
    }
}

View on GitHub (pinned to d6d39ce1c6)

Solutions

1. Pass a valid non-null caseInstanceId to the API
2. Validate the id (non-null, non-empty) at the API boundary before calling the engine
3. Trace the id's origin and fix why it is null

Example fix

// before
Map<String, VariableInstance> vars = caseService.getVariableInstances(caseInstanceId);
// after
if (caseInstanceId == null) {
    throw new IllegalArgumentException("caseInstanceId must be provided");
}
Map<String, VariableInstance> vars = caseService.getVariableInstances(caseInstanceId);

Objects.requireNonNull(caseInstanceId, "caseInstanceId is required");

boolean hasId = caseInstanceId != null && !caseInstanceId.isEmpty();

try { return caseService.getVariables(caseInstanceId); } catch (FlowableIllegalArgumentException e) { log.error("Null caseInstanceId"); throw e; }

When it happens

Trigger: Calling caseService.getVariables(caseInstanceId) / getVariableInstances with a null caseInstanceId, typically when the id comes from an unset field, failed lookup, or unvalidated request payload.

Common situations: REST endpoint where the id path/query parameter was absent; bean property never populated; result of an earlier query that returned null and was passed on unguarded.

Related errors

• variableName is null
• text is null
• bytes array is null
• Deployment id is null
• Deployment ids is null

AI-assisted analysis of flowable/flowable-engine@d6d39ce1c6 (2026-09-11). Data as JSON: /api/errors/d2de7eb91048cba7. Report an issue: GitHub.