public void run() {
    try {
      diagnosticMesg = showJobFailDebugInfo();
    } catch (IOException e) {
      console.printError(e.getMessage());
    }
  }
JobDebugger takes a RunningJob that has failed and grabs the top 4 failing
tasks and outputs this information to the Hive CLI.
ql/src/java/org/apache/hadoop/hive/ql/exec/mr/JobDebugger.java