Hey,
The SerDe interface allows you to instruct Hive as to how a record be processed. A SerDe is a combination of a Serializer and a Deserializer. The Deserializer interface takes a string or binary representation of a record, and translate it into a Java object that Hive can manipulate. The Serializer, however, will take a Java object that Hive has been working with, and turn it into something that Hive can write to HDFS or another supported system.