java generics and the addAll method
- by neesh
What is the correct type of argument to the addAll(..) method in Java collections? If I do something like this:
Collection<HashMap<String, Object[]>> addAll = new ArrayList<HashMap<String, Object[]>>();
// add some hashmaps to the list..
currentList.addAll(newElements); //currentList is of type: List<? extends Map<String, Object[]>>
I understand I need to initialize both variables. However, I get a compilation error (from eclipse):
Multiple markers at this line
- The method addAll(Collection<? extends capture#1-of ? extends Map<String,Object[]>>) in the type List<capture#1-of ? extends Map<String,Object[]>> is not applicable for the arguments (List<capture#2-of ? extends
Map<String,Object[]>>)
- The method addAll(Collection<? extends capture#1-of ? extends Map<String,Object[]>>) in the type List<capture#1-of ? extends Map<String,Object[]>> is not applicable for the arguments
(Collection<HashMap<String,Object[]>>)
what am I doing wrong?
