CODEWITHSUNDEEP
javagenerics
isatin
isatin

Reputation: 189

How to get class instances of generic types in generic methods

I have a generic method, how could I get the class of T?

class MyClass
{
    static <T> void foo(T t)
    {
        // how to get T.class
    }
}

t.getClass() gets the most derived class, but T could be a super class so it does not work in case of MyClass.<Collection>foo(new ArrayList()).

Upvotes: 1

Views: 708

Answers (1)

nyname00
nyname00

Reputation: 2566

If you want to keep your signature it is not possible. However, there's a way to solve this by providing the type as a separate argument.

static <T> void foo(T t, Class<T> cls) {
   // use cls
}

Then instead of invoking

MyClass.<Collection> foo(new ArrayList());

you call

MyClass.foo(new ArrayList(), Collection.class);

Upvotes: 2

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