public static Hive get(Configuration c, Class<?> clazz) throws HiveException {
    return get(c instanceof HiveConf ? (HiveConf)c : new HiveConf(c, clazz));
  }
This class has functions that implement meta data/DDL operations using calls
to the metastore.
It has a metastore client instance it uses to communicate with the metastore.

It is a thread local variable, and the instances is accessed using static
get methods in this class.
ql/src/java/org/apache/hadoop/hive/ql/metadata/Hive.java