Someone

				else if(e.getSource() == jmenuitemDigit){


			        DecimalFormat df = new DecimalFormat();

					String inputString = getDisplayString();
					if (inputString.indexOf(",") > 0){
						df.setGroupingSize(0);
						BigDecimal bd= new BigDecimal (labelOutPut.getText());

   			        	String bytesString = df.format(bd);
						setDisplayString(bytesString);
					}
					else if (inputString.indexOf(",") <= 0){
						df.setGroupingSize(3);
						BigDecimal bd= new BigDecimal (labelOutPut.getText());

   			        	String bytesString = df.format(bd);
						setDisplayString(bytesString);
					}

				}