apache/hadoop · error · RuntimeException

Unexpected type of tasks in the list...

Error message

Unexpected type of tasks in the list...

What it means

Error "Unexpected type of tasks in the list..." thrown in apache/hadoop.

Source

Thrown at hadoop-tools/hadoop-rumen/src/main/java/org/apache/hadoop/tools/rumen/ParsedJob.java:154

   * @return the list of other tasks of this job
   */
  public List<ParsedTask> obtainOtherTasks() {
    List<LoggedTask> tasks = super.getOtherTasks();
    return convertTasks(tasks);
  }

  /** As we know that this list of {@link LoggedTask} objects is actually a list
   * of {@link ParsedTask} objects, we go ahead and cast them.
   * @return the list of {@link ParsedTask} objects
   */
  private List<ParsedTask> convertTasks(List<LoggedTask> tasks) {
    List<ParsedTask> result = new ArrayList<ParsedTask>();

    for (LoggedTask t : tasks) {
      if (t instanceof ParsedTask) {
        result.add((ParsedTask)t);
      } else {
        throw new RuntimeException("Unexpected type of tasks in the list...");
      }
    }
    return result;
  }

  /** Dump the extra info of ParsedJob */
  void dumpParsedJob() {
    LOG.info("ParsedJob details:" + obtainTotalCounters() + ";"
        + obtainMapCounters() + ";" + obtainReduceCounters()
        + "\n" + obtainJobConfpath() + "\n" + obtainJobAcls()
        + ";Q=" + (getQueue() == null ? "null" : getQueue().getValue()));
    List<ParsedTask> maps = obtainMapTasks();
    for (ParsedTask task : maps) {
      task.dumpParsedTask();
    }
    List<ParsedTask> reduces = obtainReduceTasks();
    for (ParsedTask task : reduces) {
      task.dumpParsedTask();

View on GitHub (pinned to 2add963021)

Solutions

1. Ensure all entries in the task list are of the expected ParsedTask subtype; the list contains an unexpected type.

When it happens

Trigger: ParsedJob encounters a task object of an unexpected runtime type in the job's task list, indicating corrupted deserialized job data.

Common situations: See trigger scenarios.

AI-assisted analysis of apache/hadoop@2add963021 (2026-08-22). Data as JSON: /api/errors/739cd3133a43b6a8. Report an issue: GitHub.