Stacked Bar chart

Hello everyone ,
I am a newbie. I have a problem with the stacked bar chart . I use the code similiar to vaadin demo charts for stacked bar chart, but i have relatively high data to be displayed but i see only 1/4th of my datas are displayed.

     Chart chart = new Chart(ChartType.BAR);
     chart.setWidth(100, Unit.PERCENTAGE);
     chart.setHeight(100, Unit.PERCENTAGE);    
    
     Configuration conf = chart.getConfiguration();       
     
     List<Wearerclass> wearerslist=null;    
      wearerslist= // i set the list here            
   
     String wearername[]=new String[wearerslist.size()]

;
Long inventoryQuantity=new Long[wearerslist.size()]
;
Long realQuantity=new Long[wearerslist.size()]
;

     if(wearerslist.size()>0)
     {
     for(int i=0; i<wearerslist.size();i++)
     {                         
         wearername[i]

= wearerslist.get(i).getWearer().getFirstname()+" "+wearerslist.get(i).getWearer().getName() ;
inventoryQuantity[i]
= wearerslist.get(i).getInventoryQuantity();
realQuantity[i]
= wearerslist.get(i).getRealQuantity();
}
}
XAxis x = new XAxis();
x.setCategories(wearername);
conf.addxAxis(x);

     YAxis y = new YAxis();
     y.setMin(0);         
     conf.addyAxis(y);

  // have tooltip and legend      
    
     PlotOptionsSeries plot = new PlotOptionsSeries();
     plot.setStacking(Stacking.NORMAL);
     conf.setPlotOptions(plot);
     
     conf.addSeries(new ListSeries("inventory",inventoryQuantity));
     conf.addSeries(new ListSeries("real", realQuantity));        
      chart.drawChart(conf);
     getReportLayout().addComponent(chart);

i could see there are 83 datas to be displayed on the x axis,(behaving like the y axis in this chart) but i see only 22 bars are displayed.
Is it from the setcategories? that display only one category?
Can anyone point out what is wrong here pleaseā€¦