flowable/flowable-engine · error · FlowableObjectNotFoundException

task doesn't exist

Error message

task ${taskId} doesn't exist

What it means

GetTaskVariableCmd throws FlowableObjectNotFoundException (with Task.class) when the task service returns no TaskEntity for the given taskId. The variable lookup cannot proceed without an existing task.

Solutions

1. Verify existence first: cmmnTaskService.createTaskQuery().taskId(taskId).singleResult()
2. For completed tasks use cmmnHistoryService.createHistoricTaskInstanceQuery() and historic variable queries
3. Make sure the id comes from the CMMN engine's task service, not the BPMN one
4. Handle the FlowableObjectNotFoundException in callers that accept user-supplied task ids

Example fix

// before
Object value = cmmnTaskService.getVariable(taskId, varName); // throws if task gone
// after
Task t = cmmnTaskService.createTaskQuery().taskId(taskId).singleResult();
Object value = (t != null)
    ? cmmnTaskService.getVariable(taskId, varName)
    : cmmnHistoryService.createHistoricVariableInstanceQuery().taskId(taskId).variableName(varName).singleValue();

Task t = cmmnTaskService.createTaskQuery().taskId(taskId).singleResult();
if (t == null) {
    throw new IllegalArgumentException("No CMMN task for id " + taskId);
}

boolean taskExists(String taskId) {
    return taskId != null && cmmnTaskService.createTaskQuery().taskId(taskId).count() > 0;
}

try {
    Object value = cmmnTaskService.getVariable(taskId, variableName);
} catch (FlowableObjectNotFoundException e) {
    // Task.class entity missing: fall back to historic variable query or return 404
}

When it happens

Trigger: Calling cmmnTaskService.getVariable(taskId, name) with a taskId that has no matching CMMN task — wrong id, task completed and moved to history, or id from the BPMN engine instead of CMMN.

Common situations: Cross-engine id confusion (BPMN taskService vs cmmnTaskService); querying after the case/task was terminated and removed; stale ids cached in an external UI across environment switches.

Understand the failure class

Background: "Not found" and "does not exist" errors: why "Task not found", "No such folder", and "Can't find" fire when a lookup comes back empty — this error's family across 14 libraries.

Related errors

• Task not found with id
• Cannot find case definition for id:
• Cannot find case definition with id
• Cannot find case definition with id
• Cannot find case instance for id

AI-assisted analysis of flowable/flowable-engine@d6d39ce1c6 (2026-09-11). Data as JSON: /api/errors/f2fa938614692d74. Report an issue: GitHub.

Appendix: source

Thrown at modules/flowable-cmmn-engine/src/main/java/org/flowable/cmmn/engine/impl/cmd/GetTaskVariableCmd.java:57

        this.taskId = taskId;
        this.variableName = variableName;
        this.isLocal = isLocal;
    }

    @Override
    public Object execute(CommandContext commandContext) {
        if (taskId == null) {
            throw new FlowableIllegalArgumentException("taskId is null");
        }
        if (variableName == null) {
            throw new FlowableIllegalArgumentException("variableName is null");
        }

        CmmnEngineConfiguration cmmnEngineConfiguration = CommandContextUtil.getCmmnEngineConfiguration(commandContext);
        TaskEntity task = cmmnEngineConfiguration.getTaskServiceConfiguration().getTaskService().getTask(taskId);

        if (task == null) {
            throw new FlowableObjectNotFoundException("task " + taskId + " doesn't exist", Task.class);
        }

        Object value;

        if (isLocal) {
            value = task.getVariableLocal(variableName, false);
        } else {
            value = task.getVariable(variableName, false);
        }

        return value;
    }
}

View on GitHub (pinned to d6d39ce1c6)