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java Programming Glossary: contravariantwhy polymorphism doesn't treat generic collections and plain arrays the same way? http://stackoverflow.com/questions/10770585/why-polymorphism-doesnt-treat-generic-collections-and-plain-arrays-the-same-way valid. However you cannot safely read anything from this contravariant structure assuming that you will get a number. Number myNum..
Demonstrate covariance and contravariance in Java? http://stackoverflow.com/questions/2501023/demonstrate-covariance-and-contravariance-in-java Super void doSomething Object parameter Sub#doSomething is contravariant because it takes a parameter of a superclass of the parameter.. List extends Object covariantList aList List super String contravariantList aList You can now access all methods of covariantList that.. will always be of type Object The opposite is true for contravariantList You can access all methods with generic parameters you know..
Java Generics WildCard Question: List<? extends A> http://stackoverflow.com/questions/5495383/java-generics-wildcard-question-list-extends-a share improve this question Method arguments are contravariant in the subtype and by the definition of the wildcard for every..
Covariance, Invariance and Contravariance explained in plain English? http://stackoverflow.com/questions/8481301/covariance-invariance-and-contravariance-explained-in-plain-english f is covariant if A &le B implies that f A &le f B f is contravariant if A &le B implies that f B &le f A f is invariant if neither.. where List is declared by class List T ... Is f covariant contravariant or invariant Covariant would mean that a List String is a subtype.. would mean that a List String is a subtype of List Object contravariant that a List Object is a subtype of List String and invariant..
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