Member Avatar for JamesCherrill

The sort methods for collections specifies that the parameter must be a collection of objects that implement Comparable for their own class or superclass, eg

public static <T extends Comparable<? super T>> void sort(List<T> list)

Can anyone tell me how to define an ArrayList that will only accept such objects?
I want to say

ArrayList<T extends Comparable<? super T>>  eg = new ArrayList<String>();

But that doesn't compile. I could use

ArrayList<? extends Comparable<?>> ok = new ArrayList<String>();

but that's a bit too general (although the exceptions would be weird anyway).
I know I'm going to look silly when someone points out the obvious answer, but please do it anyway.
Thanks
J

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Member Avatar for ~s.o.s~

AFAIK, not possible since there is nothing which can be used to infer the type T in there. I'm assuming here that the aim is to ensure a Collection satisfies a given criteria. In that case, the simplest solution would be to create a separate method for the piece of code which relies on the above assumption and have the method signature same as that of the Collections.sort method.

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