I am trying to use bounded types with generics to create generic objects of subclasses (these implement an interface). But I am getting type mismatch errors when initializing objects with the subclasses. Here is the interface: Here’s the class that implements this interface: Now I created 2 classes (SegmentPageScanResult and ItemProcessor) with the bounded generic type as: and When I
Tag: bounded-wildcard
Upper bounded wildcard as a Map Value – how to provide a default Value with getOrDefault()
I have the following map Sometimes there is a List and sometimes there is a Set as a value. Now I’d like to get value, but there is a problem, it does not compile. I know I can do something like this: But I want to understand how getOrDefault() method is supposed to work with wild-card generics. Answer The short
List<? super List> and List<? extends List> and how to use it correctly?
Consider the following snippet: Here I am trying to understand how to interpret these two statements Expression:1 Here we say that the List on the RHS must be such that all the elements of the list will satisfy the condition ? super List<? super Integer> but doubleList / integerList / numberList are not satisfying this condition anyhow – as we