Java Collection Framework

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a - 16 Dec 2005 04:44 GMT

For Collection interface, the declaration of toArray() is:
<T> T[] toArray(T[] a);
Why do we have <T> at the start of the method declaration?
Thanks a lot

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Roedy Green - 16 Dec 2005 05:03 GMT

>For Collection interface, the declaration of toArray() is:
><T> T[] toArray(T[] a);
>Why do we have <T> at the start of the method declaration?
>Thanks a lot

see http://mindprod.com/jgloss/generics.html

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Canadian Mind Products, Roedy Green.
http://mindprod.com Java custom programming, consulting and coaching.

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Thomas Weidenfeller - 16 Dec 2005 08:31 GMT

> For Collection interface, the declaration of toArray() is:
> <T> T[] toArray(T[] a);
> Why do we have <T> at the start of the method declaration?

Because the "genius" that came up with the idea for Java generic decided
that this should be the syntax when you have a parametric (generic)
method and need to provide a type parameter.

And you need to have th <T>, otherwise the compiler would not know that
the two T[] in the method signature refer to a type parameter, instead
of just a 'class T".

/Thomas

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