Question

why does

List<Object> objectList; = some objects

List<Object> getList() 
{
  return objectList; //or return new List<Object>(objectList);
}

return a list with all items referenced to the original list’s items?

Thanks.

Answer 1

In the first case you just return a reference to the list.

In the second case (new List<Object>(list)) the objects are not copied: only the references are copied! You have to clone each item in the collection to return a deep copy of the list.

EDIT:

Iterate through your whole list and create a copy of each of your objects and put them into a new list.

See this for creating deep copies of custom objects. I would suggest not to use the interface ICloneable. Make some research to learn why. 🙂