Why doesn't Java autobox int[] to Integer[]?

Question

I have this method:

void stuff(Object[] array){
    // .. do stuff with the array
}

And trying to do this:

stuff(intArray);

It doesn't compile. I have to manually convert my int[] to an Integer[].

Isn't autoboxing supposed to take care of this stuff for me? Why doesn't it?

Also since turns out the Java language doesn't do this natively, why isn't there a utility in the JDK to do this stuff? Isn't this why we have a standard library?

score 3 · Accepted Answer · answered Sep 15 '14 at 22:11

3

autoboxing doesn't work for array, autoboxing uses static valueOf() method of wrapper class to convert primitive to its wrapper Object

Autoboxing is the automatic conversion that the Java compiler makes between the primitive types and their corresponding object wrapper classes. For example, converting an int to an Integer, a double to a Double, and so on. If the conversion goes the other way, this is called unboxing.

answered Sep 15 '14 at 22:11

jmj

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Why not? Damn, Java has some annoying details.. – Aviv Cohn Sep 15 '14 at 22:12
1

@AvivCohn Java does autoboxing to convert primitive types to their wrapper classes. An array is not a primitive type. – azurefrog Sep 15 '14 at 22:13
because it is designed to support wrapper class with primitive literal value, and `int[]` is not a primitive literal – jmj Sep 15 '14 at 22:13
1

Aviv, just don't use Arrays, its bad anyway, use a list. – David Limkys Sep 15 '14 at 22:14
This doesn't answer the question in my opinion. It just confirms that autoboxing doesn't work in this case. – wvdz Sep 15 '14 at 22:16
@popovitsj _the Java compiler makes between the primitive types and their corresponding object wrapper classes_ `int[]` is not a primitive type. – Sotirios Delimanolis Sep 15 '14 at 22:17

Why doesn't Java autobox int[] to Integer[]?

1 Answers1