import java.sql.*;

public class Main {

    static Connection conn;

    static Statement stat;

    static ResultSet rs;

    public static void main(String[]args){

        try{

            try {

                Class.forName("oracle.jdbc.driver.OracleDriver");

            } catch (ClassNotFoundException e) {

                // TODO Auto-generated catch block

                e.printStackTrace();

            }

            conn=DriverManager.getConnection("jdbc:oracle:thin:@192.168.140.110:1521/ora11g","ora","ora");

            stat=conn.createStatement();

            rs=stat.executeQuery("select * from all_users");

            while(rs.next()){

                System.out.println(rs.getString("username"));

            }

        }catch(SQLException e){

            e.printStackTrace();

        }finally{

            if(rs!=null){

                try {

                    rs.close();

                } catch (SQLException e) {

                    // TODO Auto-generated catch block

                    e.printStackTrace();

                }

                rs=null;

            }

            if(conn!=null){

                try {

                    conn.close();

                } catch (SQLException e) {

                    // TODO Auto-generated catch block

                    e.printStackTrace();

                }

                conn=null;

            }

        }

    }

}