@Override
        public void run() {
          try {
            endTransactionAndCleanup(false, driverContext.getTxnManager());
          } catch (LockException e) {
            LOG.warn("Exception when releasing locks in ShutdownHook for Driver: " +
                e.getMessage());
          }
        }
Handles transaction related duties of the Driver.
ql/src/java/org/apache/hadoop/hive/ql/DriverTxnHandler.java