@Override
  public String getDisplayString(String[] children) {
    return getStandardDisplayString("GenericUDFExceptionInVertex", children, ",");
  }
This class implements the UDF which can throw an exception in arbitrary vertex (typically mapper)
/ task / task attempt. For throwing exception in reducer side, where most probably
GroupByOperator codepath applies, GenericUDAFExceptionInVertex is used.
ql/src/java/org/apache/hadoop/hive/ql/udf/generic/GenericUDFExceptionInVertex.java