protected void checkState() throws SQLException {

        // If all the three i.e.  conn, ps & rs are
        // simultaneously null implies we are not connected
        // to the db, implies undesirable state so throw exception

        if (conn == null && ps == null && rs == null ) {
            throw new SQLException(resBundle.handleGetObject("jdbcrowsetimpl.invalstate").toString());
        }
    }
Initializes the given <code>RowSetMetaData</code> object with the values
in the given <code>ResultSetMetaData</code> object.

@param md the <code>RowSetMetaData</code> object for this
          <code>JdbcRowSetImpl</code> object, which will be set with
          values from rsmd
@param rsmd the <code>ResultSetMetaData</code> object from which new
            values for md will be read
@throws SQLException if an error occurs
src/main/java/org/replicadb/rowset/sun/rowset/JdbcRowSetImpl.java