@Override
  public Object evaluate(DeferredObject[] arg0) throws HiveException {

    if (arg0.length != 1) {
      LOG.error("UDFHelloTest expects exactly 1 argument");
      throw new HiveException("UDFHelloTest expects exactly 1 argument");
    }

    if (arg0[0].get() == null) {
      LOG.warn("Empty input");
      return null;
    }

    Text data = (Text) converters[0].convert(arg0[0].get());

    String dataString = data.toString();

    result.set(greeting + dataString);

    return result;
  }
UDF to obfuscate input data appending "Hello "
ql/src/test/org/apache/hadoop/hive/ql/exec/vector/UDFHelloTest.java