flowable/flowable-engine · error · FlowableObjectNotFoundException

Could not find a task with id '

Error message

Could not find a task with id '

What it means

The requested CMMN task id does not correspond to any task in the engine's ACT_RU_TASK table. getTaskFromRequestWithoutAccessCheck queries taskService.createTaskQuery().taskId(taskId) and, when no task is returned, throws FlowableObjectNotFoundException typed to Task.class.

Solutions

1. Verify the taskId exists via the task list query or the database before fetching
2. If the task is completed, use the CMMN history task endpoints instead of runtime
3. Check you are connected to the correct database/tenant where the task was created
4. Catch FlowableObjectNotFoundException and return 404 to the caller

Example fix

// before
Task t = restClient.getTask("stale-or-typo-id");
// after
List<TaskResponse> found = restClient.queryTasks(taskQuery().taskId(candidateId));
if (!found.isEmpty()) { Task t = restClient.getTask(candidateId); }

const found = await queryTasks({ taskId: id }); if (found.length === 0) throw new NotFound(id);

try { task = await getTask(id); } catch (e) { if (e.status === 404 || e instanceof FlowableObjectNotFoundException) { /* fall back to history endpoint or return 404 */ } else { throw e; } }

When it happens

Trigger: GET /cmmn-runtime/tasks/{taskId} (or any sub-resource like identity links, variables, comments) with a taskId that does not exist, was already completed/deleted, or belongs to a different engine/database.

Common situations: Stale client-side task references after task completion; wrong tenant/database; typo or truncated id; querying a historic (completed) task through the runtime API instead of the history API.

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

• Could not find task instance with id:
• Attachment with id ' ' does not have content associated…
• Cannot find process instance with id
• Cannot find process instance with id
• Cannot find task with id

AI-assisted analysis of flowable/flowable-engine@d6d39ce1c6 (2026-09-11). Data as JSON: /api/errors/f99fdba3383f3839. Report an issue: GitHub.

Appendix: source

Thrown at modules/flowable-cmmn-rest/src/main/java/org/flowable/cmmn/rest/service/api/runtime/task/TaskBaseResource.java:569

    }

    /**
     * Returns the {@link Task} that is requested and calls the access interceptor.
     * Throws the right exceptions when bad request was made or instance was not found.
     */
    protected Task getTaskFromRequest(String taskId) {
        Task task = getTaskFromRequestWithoutAccessCheck(taskId);
        if (restApiInterceptor != null) {
            restApiInterceptor.accessTaskInfoById(task);
        }

        return task;
    }

    protected Task getTaskFromRequestWithoutAccessCheck(String taskId) {
        Task task = taskService.createTaskQuery().taskId(taskId).singleResult();
        if (task == null) {
            throw new FlowableObjectNotFoundException("Could not find a task with id '" + taskId + "'.", Task.class);
        }

        return task;
    }

    protected List<Task> getTasksFromRequest(Collection<String> taskIds) {
        return taskService.createTaskQuery().taskIds(taskIds).list();
    }
}

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