Casting primitive data type array to an OO array

Question

Is there an elegant, clean way for converting primitive data type double array to OO Double array (e.g. double[] into Double[])?

There are some nice solutions out there, e.g.

int[] intArray = { ... };
Integer[] what = Arrays.stream( intArray ).boxed().toArray( Integer[]::new );
Integer[] ever = IntStream.of( intArray ).boxed().toArray( Integer[]::new );

(taken from here), but this requires Java 8. Is there a similar elegant, performant way for Java 7 and below?

I did some search online couple weeks ago about this and people asked similar questions on SO also, seems like the only way is going through a loop. — OPK
– OPK, Commented Dec 29, 2015 at 15:43
can anyone comment on the efficiency when using stream with java 8? — OPK
– OPK, Commented Dec 29, 2015 at 15:45
@RPresle I clearly differentiate to this post; the post has solutions for Java 8, but no non-loop solution for < Java 8. — Michael Dorner
– Michael Dorner, Commented Dec 29, 2015 at 15:48

Manos Nikolaidis · Accepted Answer · 2015-12-29 15:59:25Z

2

If you want a one liner that compiles with Java 7, you can use ArrayUtils from Apache Commons. E.g.

Integer[] what = ArrayUtils.toObject(intArray);

Works for any primitive type. That's probably more "elegant" and "clean" than the Java 8 code you posted. If you want to avoid libraries like Apache Commons, I am afraid you have to use a for loop.

edited Dec 29, 2015 at 15:59

answered Dec 29, 2015 at 15:50

Manos Nikolaidis

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