Null is being shown when list containing data from database is displayed through jsp

[ME@SHARMA]

I'am new to java, this question may have been asked earlier but I'm not getting the exact answer.I want to add data from database into at and display it through jsp. But empty or null values is shown i.e no data is being displayed and when I execute the same sql query which is used in code in sql server then required output is displayed. My java code is:

public List < Alarm_Bean > get_Count(String system_Name)

{

  if (system_Name.equals("MPS"))

  {
    try {
      con = getConnection();

      stmt = con.createStatement();

      String sql = " select c,system_name, 'TotalSum' as TotalSum, sum(s.c) as TotalValue from (SELECT   system_name, COUNT(distinct arrival_time) AS c FROM i2alarmlog WHERE Ack_status = 0 AND Direction='CAME' AND system_name in('I2-tciu database','i2-vcs logging','Indus1 Vacuum','Indus2 TCIU','Indus2 Vacuum','Septum_SIP2','TL3 Vacuum') GROUP BY system_name ) s     ";

      stmt.executeQuery(sql);
      rs = stmt.getResultSet();



      while (rs.next()) {
        Alarm_Bean obj = new Alarm_Bean();


        obj.setSystem_name(rs.getString("system_name"));

        obj.setC(rs.getString("c"));
        at.add(obj);
      }

    } catch (Exception e) {
      System.out.println("\nException " + e);
    } finally {
      closeConnection(stmt, rs, con);
    }
  }
  //System.out.println(at);

  return at;

}

[Tolls]

Any exception in your logs?

The second thing is to log everything in that method.
Log entering the result set loop, and the values in the columns for each row.
Log the values returned in the List.

[ME@SHARMA]

I didn't get you.Will you please elaborate it with example or code sample.

[Tolls]

I'm simply pointing out that you need to log everything in order to debug your code.
At the moment you are making assumptions about what is going on without (as far as I can see) enough logging in the code to tell you exactly what is happening.

[dswastik]

Does the following print anything?

System.out.println("\nException " + e); and better use e.printStackTrace() to get the detailed exception stack.

[gimbal2]

at.add(obj); // where does 'at' come from?

[ME@SHARMA]

no ,nothing is being printed .at is defined as a global variable as:-

private List<String> at= new ArrayList<String>();

[gimbal2]

If it is a class property, then why are you returning it from the method? The way you have it now, each call to get_count will just keep appending new elements to this one list.

That is probably nothing to do with your current problem, but it is a design smell that might lead to other problems if you're not careful.

[ME@SHARMA]

Ok, but how to resolve this current problem..??

[gimbal2]

You solve it like you solve all other problems, first you need to find the cause. Hence the replies for doing more debugging.

[Tolls]

no ,nothing is being printed

Show us the code with the extra logging added.
Include a logging statement at the very start of the method, just to make sure this is actually being called.