Arrays.asList().contains() on Double vs double arrays [duplicate]

Answer 1

Your first call to Arrays.asList is actually returning a List - it's autoboxing the argument, because a double[] isn't a T[]... generics don't allow for primitive types as type arguments.

If you want to convert a double[] into a List, you either need to do it manually or use a third-party library to do it. For example:

public List toList(double[] doubles) {
    List list = new ArrayList<>(doubles.length);
    for (double x : doubles) {
        list.add(x);
    }
    return list;
}

Note that unlike Arrays.asList any subsequent changes to the array will not be reflected in the list or vice versa - it's a copy, not a view.