java.sql.SQLException: Illegal operation on empty result set. when query return only 1 row

Question

in this code i am trying to get a row from the id in for lopp variable and printing it into a labels which are created on the basis of count though count is less then the total number of rows in the database the the returns a correct ans when i executed it in mysql. but when i use the rs.getstring("concept name") in the last line to get the contents of "concept name" column i get empty result set error.

Class.forName("com.mysql.jdbc.Driver");
con = DriverManager.getConnection("jdbc:mysql://localhost:3306/niitdb","root","");

for(pos=0; pos<7; pos++){

     SQL = "SELECT `concept name` FROM `concepts " +course+ "` where `concept id` = " + pos+1;   
     Statement stmt = con.createStatement();
     rs = stmt.executeQuery(SQL);
     rs.next();
     Cname[cnt] = new JLabel(rs.getString("concept name")); // error is on this line 
}

Answer 1

The JDBC driver may not handle the column name with blanks correctly. I would try it as

SELECT `concept name` as concept_name FROM ...

and then

if (rs.next())
{
    Cname[cnt] = new JLabel(rs.getString("concept_name"));
}

as you should not call rs.next() without testing the result, and only proceeding to get column values if it was true.