my sql query don't work

my sql query don't work

i have one problem with database in java
my code is ( its only one small part of my project)
public void Read_from_DB(int exhibition_id){
Statement stmt = null;
Connection connect = null;
try {
connect=MYConnection.new_connection();
stmt = connect.createStatement();
QuestionCatalog.get_QuestionCatalog_instance().setShow_quest(new
ArrayList<Question>());
String sql = "SELECT * FROM question WHERE Selection=0 AND
exhibition_id="+exhibition_id;
//System.out.println(sql);
ResultSet rs = stmt.executeQuery(sql);
System.out.println("!");
System.out.println("->"+rs.getFetchSize());
while(rs.next()){
Question jd=new Question();
System.out.println("!!!");
jd.setQuestion_id(rs.getInt("Question_id"));
jd.setQuestion(rs.getString("Question"));
jd.setQuestion(rs.getString(exhibition_id));
jd.getOption_2().setContent(rs.getString("Content2"));
System.out.println("no");
QuestionCatalog.get_QuestionCatalog_instance().getShow_quest().add(jd);
System.out.println("size"+QuestionCatalog.get_QuestionCatalog_instance().getShow_quest().size());
}
}catch (Exception e) {
// TODO: handle exception
}
}
when i execute this code it dosent work my database table name is
"question" but when i change the name in this query to "Question" , don't
get any error then i think it doesn't execute my query,my main is
public static void main(String[] args) {
DB_question d=new DB_question();
d.Read_from_DB(1);
}
and "MYConnection.new_connection();" in part on of code return a
connection,( i test it in another class it work)
the result in console is :
SELECT * FROM Question WHERE Selection=0 AND exhibition_id=1
!
->0
it haven't show "!!!"that is result of "System.out.println("!!!");" then i
think it doesnt work :| thanks
p.s the picture of my db picture