sequences and rollback

Do I understand correctly that you cannot roll back sequences?

JDBC example:

      connect();
      db.setAutoCommit(false);
      Statement stmt=db.createStatement();
      stmt.executeQuery("select nextval('test_seq')");
     ... other table updates ...
      stmt.close();
      db.rollback();
      db.close();

In this example, the sequence does not roll back. .. other table updates
... do roll back.