funtion taking time to return Callback

Hi,
   Am using DWR 2.0.
   I have written a piece of code in javascript as:

   StrandSummary.buildStrandSummary(objParametersBD, function(objSummary){
        objObjectiveSummary = objSummary;
        displayStrandSummary();
   });
 
   Where StrandSummary is my java class converted to dwr. objParametersBD and objObjectiveSummary  are global javascript objects.
 
   The problem is when I call "buildStrandSummary" it is taking around 20sec to return me the callback.
When I checked the java classes, the entire logic and query building is beging done in around 2 sec.
In these classes there are around 8 getters and setters classes invlolved.

I just want to know the reason why this is taking time to return a callback.

Thanks in Advance,
Rizwan