初学java,写了一个链接Oracle的小程序,运行后报错：

初学java,写了一个链接Oracle的小程序,运行后报错：
java.sql.SQLException:无效的列索引
请问这是为什么?
附上程序：
package connection;
import java.sql.*;
public class Connectionb {
public static final void main(String args[]){
Connection con=null;
try {
Class.forName("oracle.jdbc.driver.OracleDriver");
}
catch (ClassNotFoundException e){
System.out.println(e);
}
try{
String s = "jdbc:oracle:thin:@192.168.3.98:1521:orcl";
con = DriverManager.getConnection(s,"kk","kk");
Statement stat = con.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,ResultSet.CONCUR_UPDATABLE);
ResultSet rs = stat.executeQuery("select * from TEST5");
while (rs.next()){
int DM= rs.getInt(12);
String MC=rs.getString(40);
int JB=rs.getInt(2);
int YXBZ= rs.getInt(2);
System.out.println("DM"+DM);
System.out.println("MC"+MC);
System.out.println("JB"+JB);
System.out.println("YXBZ"+YXBZ);
}
rs.close();
}
catch(SQLException e2){
System.out.println(e2);
}
}
}