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Thread: Generics

  1. #1
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    Default Generics

    Hi all.

    Managed to find a link which talks about type erasure. Or more specifically, it talks a bit about how you can avoid type erasure in generics. According to the link, a generic type can be known at runtime during some situations. Does anyone have a thought on this text? Does this mean that if you do something like this you are actually avoiding using type erasure?
    ArrayList<String> alist = new ArrayList<String>() {};
    Do not know how much this actually matters, I am just curious . The link:
    Using TypeTokens to retrieve generic parameters - JQuantLib

    Take care,
    Kerr.

    P.S.

    I confess I didnt read it very carefully, so if I have missed something or missunderstood it then that is why, lol.

    EDIT:

    Lol, just realized I forgot to give the thread a better title. Sorry about that.


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    Default Re: Generics

    Type erasure isn't something you use, it's what the compiler does. The generics syntax is a compile-time way for the compiler to check that you're using the correct types. All (most of) that type information is removed during compilation so the compiled code doesn't have it and the Java runtime can't use it. Hence 'type erasure'. See Type Erasure.

    For technical reasons, the runtime needs some type information for anonymous classes, so some type information is retained when anonymous classes are compiled. This is accessible (through messy tricks like those in the article), but it really seems like cutting off your nose to spite your face - making the syntax a tiny bit simpler or avoiding a minor inconvenience by sacrificing simplicity, robustness and performance... YMMV.
    Last edited by dlorde; May 15th, 2011 at 02:09 PM.

  3. #3
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    Default Re: Generics

    I know what type erasure is. But I confess I got kind of confused by the article. Thought that if you could avoid making casts then it could improve performance, or something. Now that I think of it I realize it would just become a mess.
    Last edited by Kerr; May 19th, 2011 at 07:51 PM.

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