Nested Generics with Wildcards

generics, java

Solution

Try

List<? extends List<?>> list = new LinkedList<List<Integer>>();

Note: you should be aware that when you use a collection like List you will only be able to use it in "read only" mode (except for adding null values).

Problem

Why does this work: ``` List<?> list = new LinkedList<Integer>(); ``` while this gives a type dismatch error: ``` List<List<?>> list = new LinkedList<List<Integer>>(); ``` Why is this? Ist there a way around this, without using raw types?

Original source