Java connect to Oracle, select data

package api;

import java.sql.*;

public class TestOracle {
    public static void main(String args[]) {
        Connection connection;
        Statement stmt;
        ResultSet rs;
      
        try {
            // Load the JDBC driver
            String driverName = "oracle.jdbc.driver.OracleDriver";
            Class.forName(driverName);

            // Create a connection to the database (get connection info from $ORACLE_HOME\NETWORK\ADMIN\tnsnames.ora)
            String serverName = "VTT_VE_HUYPV";
            String portNumber = "1521";
            String sid = "orcl";
            String url = "jdbc:oracle:thin:@" + serverName + ":" + portNumber
                    + ":" + sid;
            String username = "portal";
            String password = "abc";
            connection = DriverManager.getConnection(url, username, password);
          
            stmt = connection.createStatement();
            int offset = 0;
            int limit = 1000;
            String sql = "SELECT * FROM (SELECT rownum rn, a.* from HR.COUNTRIES a) WHERE rn > "+String.valueOf(offset)+" AND rn <= "+String.valueOf(offset + limit);
          
            // Create a scrollable ResultSet.
            stmt = connection.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,
                    ResultSet.CONCUR_READ_ONLY);
            rs = stmt.executeQuery(sql);

            // Point to the last row in resultset.
            rs.last();

            // Get the row position which is also the number of rows in the
            // ResultSet.
            int rowcount = rs.getRow();

            System.out.println("Total rows for the query: " + rowcount);

            // Reposition at the beginning of the ResultSet to take up rs.next()
            // call.
            rs.beforeFirst();
          
            while (rs.next()) {
                System.out.println(rs.getString(2) + " = " + rs.getString(3));
            }
        } catch (ClassNotFoundException e) {
            // Could not find the database driver
            System.out.println("404 DB Driver");
        } catch (SQLException e) {
            // Could not connect to the database
            e.printStackTrace();
        }
      
      
    }
}