protected String getStandardDisplayString(String name, String[] children, String delim) {
    StringBuilder sb = new StringBuilder();
    sb.append(name);
    sb.append("(");
    if (children.length > 0) {
      sb.append(children[0]);
      for (int i = 1; i < children.length; i++) {
        sb.append(delim);
        sb.append(children[i]);
      }
    }
    sb.append(")");
    return sb.toString();
  }
Some information may be set during initialize() which needs to be saved when the UDF is copied.
This will be called by FunctionRegistry.cloneGenericUDF()
ql/src/java/org/apache/hadoop/hive/ql/udf/generic/GenericUDF.java