Java Generics: List, List<Object>, List<?>
Can someone explained, as detailed as possible, the differences between the following types?
List
ListLet me m
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The shortest possible explanation is: The second item is a list that can hold any type, and you can add objects to it:
ListThe first item you list is treated as essentially equivalent to this, except you will get compiler warnings because it is a "raw type".
ListThe third is a list that can hold any type, but you cannot add anything to it:
ListBasically, you use the second form (
List) when you truly have a list that can contain any object and you want to be able to add elements to the list. You use the third form (List)when you receive the list as a method return value and you will iterate over the list but never add anything to it Never use the first form (List) in new code compiling under Java 5 or later.
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