flowable/flowable-engine · error · ActivitiObjectNotFoundException

Task '' not found

Error message

Task '' not found

What it means

Lookup failure in flowable5 GetRenderedTaskFormCmd.execute: no task entity exists with the given taskId, so its rendered form cannot be produced; indicates an unknown or already-completed/deleted task.

Source

Thrown at modules/flowable5-engine/src/main/java/org/activiti/engine/impl/cmd/GetRenderedTaskFormCmd.java:48

 */
public class GetRenderedTaskFormCmd implements Command<Object>, Serializable {

    private static final long serialVersionUID = 1L;
    protected String taskId;
    protected String formEngineName;

    public GetRenderedTaskFormCmd(String taskId, String formEngineName) {
        this.taskId = taskId;
        this.formEngineName = formEngineName;
    }

    @Override
    public Object execute(CommandContext commandContext) {
        TaskEntity task = commandContext
                .getTaskEntityManager()
                .findTaskById(taskId);
        if (task == null) {
            throw new ActivitiObjectNotFoundException("Task '" + taskId + "' not found", Task.class);
        }

        if (task.getTaskDefinition() == null) {
            throw new ActivitiException("Task form definition for '" + taskId + "' not found");
        }

        TaskFormHandler taskFormHandler = task.getTaskDefinition().getTaskFormHandler();
        if (taskFormHandler == null) {
            return null;
        }

        FormEngine formEngine = commandContext
                .getProcessEngineConfiguration()
                .getFormEngines()
                .get(formEngineName);

        if (formEngine == null) {
            throw new ActivitiException("No formEngine '" + formEngineName + "' defined process engine configuration");

View on GitHub (pinned to d6d39ce1c6)

Solutions

1. Confirm the task exists: taskService.createTaskQuery().taskId(taskId).singleResult() before rendering.
2. Re-fetch the current task id for the user/execution via taskService.createTaskQuery().taskCandidateOrAssigned(userId).list().
3. Handle the completed/deleted case in the UI by refreshing the task list instead of retrying the stale id.
4. Verify you are querying the same engine/database the task belongs to.

Example fix

// before
taskService.getRenderedTaskForm(taskId); // may throw if task gone
// after
Task task = taskService.createTaskQuery().taskId(taskId).singleResult();
if (task != null) {
    taskService.getRenderedTaskForm(taskId);
}

Task task = taskService.createTaskQuery().taskId(taskId).singleResult();
if (task == null) throw new IllegalArgumentException("Unknown task: " + taskId);

try {
    taskService.getRenderedTaskForm(taskId);
} catch (ActivitiObjectNotFoundException e) {
    // task completed/deleted — refresh task list
}

When it happens

Trigger: Calling TaskService.getRenderedTaskForm(taskId) with a task id that does not exist, or that existed but was completed/deleted before the call.

Common situations: Stale task id from a UI after the task was completed by another user or a job; hard-coded ids; calling across engines/environments (test id used against production engine); task removed by process instance deletion.

Understand the failure class

Background: Record Not Found Errors: "not found", RecordNotFound, and "was not found" — what they mean and how to fix them — this error's family across 28 libraries.

Related errors

• Process Definition '' not found
• No task found for taskId ''
• Cannot resume task with id '
• Cannot find task with id ${taskId}
• task ${taskId} doesn't exist

AI-assisted analysis of flowable/flowable-engine@d6d39ce1c6 (2026-09-11). Data as JSON: /api/errors/cac6da5ce4195bfe. Report an issue: GitHub.