flowable/flowable-engine · error · FlowableObjectNotFoundException

Cannot find task with id {taskId}

Error message

Cannot find task with id {taskId}

What it means

FlowableObjectNotFoundException thrown by ActivateTaskCmd.execute when no task exists with the supplied taskId. The command loads the task via the task service; a null result means the id is unknown, deleted, or belongs to another database/schema.

Source

Thrown at modules/flowable-engine/src/main/java/org/flowable/engine/impl/cmd/ActivateTaskCmd.java:51

    protected String userId;

    public ActivateTaskCmd(String taskId, String userId) {
        this.taskId = taskId;
        this.userId = userId;
    }

    @Override
    public Void execute(CommandContext commandContext) {
        ProcessEngineConfigurationImpl processEngineConfiguration = CommandContextUtil.getProcessEngineConfiguration(commandContext);
        
        if (taskId == null) {
            throw new FlowableIllegalArgumentException("taskId is null");
        }

        TaskEntity task = processEngineConfiguration.getTaskServiceConfiguration().getTaskService().getTask(taskId);

        if (task == null) {
            throw new FlowableObjectNotFoundException("Cannot find task with id " + taskId, Task.class);
        }

        if (task.isDeleted()) {
            throw new FlowableException(task + " is already deleted");
        }

        if (!task.isSuspended()) {
            throw new FlowableException(task + " is not suspended, so can't be activated");
        }
        
        Clock clock = processEngineConfiguration.getClock();
        Date updateTime = clock.getCurrentTime();
        task.setSuspendedTime(null);
        task.setSuspendedBy(null);
        if (task.getInProgressStartTime() != null) {
            task.setState(Task.IN_PROGRESS);
        } else if (task.getClaimTime() != null) {
            task.setState(Task.CLAIMED);

View on GitHub (pinned to d6d39ce1c6)

Solutions

1. Verify the task exists first: taskService.createTaskQuery().taskId(id).singleResult() != null.
2. Check the process instance/history to confirm the task was completed rather than deleted.
3. Confirm the engine connects to the same database schema where the task was created.
4. If the task was completed already, skip activation (a completed task cannot be suspended/activated).

Example fix

// before
taskService.activateTask(taskId);
// after
Task task = taskService.createTaskQuery().taskId(taskId).singleResult();
if (task != null) {
    taskService.activateTask(taskId);
}

Task t = taskService.createTaskQuery().taskId(taskId).singleResult();
if (t == null) {
    return; // nothing to activate
}
taskService.activateTask(taskId);

try {
    taskService.activateTask(taskId);
} catch (FlowableObjectNotFoundException e) {
    // task gone (completed/deleted); skip
}

When it happens

Trigger: taskService.activateTask(id) with an id that was never created, references a completed (and cleaned-up) task, or points at a different database/schema.

Common situations: Activating a task after the process instance was removed; multi-tenant/multi-schema setups querying the wrong schema; stale ids cached in external systems; typo'd ids from logs.

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

• Cannot resume task with id '
• Cannot find task with id ${taskId}
• task ${taskId} doesn't exist
• taskId is null
• Cannot find task with id {taskId}

AI-assisted analysis of flowable/flowable-engine@d6d39ce1c6 (2026-09-11). Data as JSON: /api/errors/1ebc8db68cecc147. Report an issue: GitHub.