private CSVWriter newWriter(final Writer writer, char separator, char quote, char escape) {
    if (CSVWriter.DEFAULT_ESCAPE_CHARACTER == escape) {
      return new CSVWriter(writer, separator, quote, '"', "");
    } else {
      return new CSVWriter(writer, separator, quote, escape, "");
    }
  }
OpenCSVSerde use opencsv to deserialize CSV format.
Users can specify custom separator, quote or escape characters. And the default separator(\),
quote("), and escape characters(\) are the same as the opencsv library.
serde/src/java/org/apache/hadoop/hive/serde2/OpenCSVSerde.java