apache/hadoop · error · IllegalArgumentException

TaskId string : {str} is not properly formed

Error message

TaskId string : {str} is not properly formed

What it means

Error "TaskId string : {str} is not properly formed" thrown in apache/hadoop.

Source

Thrown at hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-core/src/main/java/org/apache/hadoop/mapred/JVMId.java:171

  public static JVMId forName(String str) 
    throws IllegalArgumentException {
    if(str == null)
      return null;
    try {
      String[] parts = str.split("_");
      if(parts.length == 5) {
        if(parts[0].equals(JVM)) {
          boolean isMap = false;
          if(parts[3].equals("m")) isMap = true;
          else if(parts[3].equals("r")) isMap = false;
          else throw new Exception();
          return new JVMId(parts[1], Integer.parseInt(parts[2]),
              isMap, Integer.parseInt(parts[4]));
        }
      }
    }catch (Exception ex) {//fall below
    }
    throw new IllegalArgumentException("TaskId string : " + str 
        + " is not properly formed");
  }

}

View on GitHub (pinned to 2add963021)

Solutions

1. Pass a properly formed task ID string (e.g. task_<jtIdentifier>_<jobId>_<m|r>_<taskId>) when constructing the JVMId.

When it happens

Trigger: Thrown at hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-core/src/main/java/org/apache/hadoop/mapred/JVMId.java:171 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of apache/hadoop@2add963021 (2026-08-22). Data as JSON: /api/errors/e209f8b5130a860a. Report an issue: GitHub.