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Java Arrays.asList on primitive array type produces unexpected List type [duplicate]

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Arrays.asList() not working as it should?

Apparently the return type of Arrays.asList(new int[] { 1, 2, 3 }); is List<int[]>. This seems totally broken to me. Does this have something to do with Java not autoboxing arrays of primitive types?

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Finbarr Avatar asked Jan 06 '11 17:01

Finbarr


2 Answers

The problem is that Arrays.asList takes a parameter of T... array. The only applicable T when you pass the int[] is int[], as arrays of primitives will not be autoboxed to arrays of the corresponding object type (in this case Integer[]).

So you can do Arrays.asList(new Integer[] {1, 2, 3});.

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sjr Avatar answered Oct 27 '22 16:10

sjr


Try:

Arrays.asList(new Integer[] { 1, 2, 3 });

Note Integer instead of int. Collections can contain only objects. No primitive types are allowed. int is not an object, but int[] is, so this is why you get list with one element.

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Rekin Avatar answered Oct 27 '22 18:10

Rekin