@Override
  public String getDisplayString(String[] children) {
    assert (children.length == 1);
    return getStandardDisplayString("GenericUDFTestGetJavaString", children);
  }
A test GenericUDF to return native Java's string type
itests/util/src/main/java/org/apache/hadoop/hive/ql/udf/generic/GenericUDFTestGetJavaString.java