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up vote 2 down vote favorite
1

I'm trying to make a List from a primitive array

int[] values={4,5,2,3,42,60,20};
List<Integer> greaterThan4 =
Arrays.stream(values)
        .filter(value -> value > 4)
        .collect(Collectors.toList());

But the last function collect gives me an error because it wants other arguments. It wants 3 arguments Supplier, ObjIntConsumer and BiConsumer.

I don't understand why it wants 3 arguments when I have seen different examples that just use collect(Collectors.toList()); and get the list.

What I'm doing wrong?

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3 Answers 3

up vote 8 down vote accepted

Yes this is because Arrays.stream returns an IntStream. You can call boxed() to get a Stream<Integer> and then perform the collect operation.

List<Integer> greaterThan4 = Arrays.stream(values)
                                   .filter(value -> value > 4)
                                   .boxed()
                                   .collect(Collectors.toList());
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3  
+ 1 for finding the real problem and the real solution –  fge Dec 19 '14 at 19:46
up vote 1 down vote

You can change int[] values={4,5,2,3,42,60,20}; to Integer[] values={4,5,2,3,42,60,20}; because currently you are passing an array of primitive type(int) but should you pass array of object i.e. Integer

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up vote 1 down vote

You're using an array of primitives for one thing, not Integer. I suggest you use Arrays.asList(T...) like

Integer[] values={4,5,2,3,42,60,20};
List<Integer> al = new ArrayList<>(Arrays.asList(values));
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