JComboBox: want first entry to be blank entry

I have a jcombobox which values come from a list. I want to first value to be blank from dropdown list. The way I approached it was by putting new object of the list type in first as example shows :

 final List<Object> list = getObjectsList();
  list.add(new Object()); 

But this results in null pointer and if do

list.add(null);

this solves the issue but then gives me another prob elsewhere with a Comparator method. So any work a rounds would be great thanks.