我错过了什么，或者varargs打破Arrays.asList？

Question

  private void activateRecords(long[] stuff) {
    ...
    api.activateRecords(Arrays.asList(specIdsToActivate));
  }

Shouldn't this call to Arrays.asList return a list of Long s? Instead it is returning a List<long[]>

public static <T> List<T> asList(T... a)

The method signature is consistent with the results, the varargs throws the entire array into the list. It's the same as new ArrayList(); list.add(myArray) new ArrayList(); list.add(myArray) And yes, I know it's meant to be used like this: Arrays.asList(T t1, T t2, T t3)

I guess what I'm getting at, is instead of the varargs form, why can't I just have my old asList method (at least I think this is how it used to work) that would take the contents and put them individually into a list? Any other clean way of doing this?

Answer 1

That's because long[] and Long[] are different types.

In the first case T is long[], in the second T is Long.

How to fix this? Don't use long[] in the first place?

Answer 2

Autoboxing cannot be done on arrays. You are allowed to do:

private List<Long> array(final long[] lngs) {
    List<Long> list = new ArrayList<Long>();
    for (long l : lngs) {
        list.add(l);
    }
    return list;
}

or

private List<Long> array(final long[] lngs) {
    List<Long> list = new ArrayList<Long>();
    for (Long l : lngs) {
        list.add(l);
    }
    return list;
}

(notice that the iterable types are different)

eg

Long l = 1l;

but not

Long[] ls = new long[]{1l}