How can I create a list with N objects?

If I got your question right:

List <Object> getList(int numOfElements){
     return IntStream.range(0, numOfElements)
              .mapToObj(Object::new) // or x -> new Object(x).. or any other constructor 
              .collect(Collectors.toList()); 
}

If you want the same object n times:

Collections.nCopies(n, T)