The given code creates a mysql connection and use the update query to update the record. To update record, we write query ?UPDATE student SET fieldName=??? WHERE fieldName=?? . You can SET value corresponding to any another field by putting WHERE Clause.

package roseindia.net;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.sql.Statement;

public class JDBCsetFetchSize {
        public static void main(String[] args) throws SQLException {
                Connection con = null
                Statement stmt = null; 
                ResultSet rs = null;

                String conUrl = "jdbc:mysql://localhost:3306/";
                String driverName = "com.mysql.jdbc.Driver";
                String databaseName = "student";
                String usrName = "root";
                String usrPass = "root";
                try {
                        // Loading Driver
                        Class.forName(driverName). newInstance();
                } catch (ClassNotFoundException e) {
                        System.out.println(e.toString());
                }
                try {
                        // Getting Connection
                        con = DriverManager.getConnection(conUrl + databaseName, usrName,
                                        usrPass);
                        stmt = con.createStatement();

                        String query = "UPDATE student SET  name=?Rose? WHERE roll=3'";

            }

                } catch (Exception e) {
                        System.out.println(e.toString());
                } finally {
                        // Closing Connection
                        con.close();
                        stmt.close();
                }
        }
}