public FunctionInfo registerUDF(String functionName,
                                  Class<? extends UDF> UDFClass, boolean isOperator) {
    return registerUDF(functionName, UDFClass, isOperator, functionName.toLowerCase());
  }
@deprecated From next release, replaced by {@link #registerUDF(String, Class, boolean, String)}
Deprecated because method unnecessarily accepts FunctionResource vararg param
ql/src/java/org/apache/hadoop/hive/ql/exec/Registry.java