Stream of integers

Question

I have the code:

int[] values = { 1, 4, 9, 16 };
Stream<Integer> ints = Stream.of(values);

which gives me compilation error. But:

int[] values = { 1, 4, 9, 16 };
Stream<Integer> ints = Stream.of(new Integer[] {1, 4, 9, 16});

doesn't give so. Why?

Answer 1

In the first example, you are passing an array of primitives ints to Stream#of which can take either an object, or an array of object. Primitives are not objects.

In the second example, it compiles becauses you pass in an array of Integer.

You can use IntStream#of which accept int arrays.

Answer 2

Because int[] and Integer[] is different types. First one is array of primitives, second one is array of objects with type Integer.

You can use IntStream.of(int[]) or Stream.of(Integer[])