Convert a Object[] of booleans to a boolean[] using streams

No, because map(Boolean::booleanValue) expands to

map((Boolean value) -> (Boolean)value.booleanValue());

(note the autoboxing inserted by the compiler, because the function passed to map() has to return an Object, not a boolean)

This is why the Java8 streams include a whole bunch of specialized classes (IntStream, LongStream, and DoubleStream). Sadly, there is no specialized stream class for boolean.

The only streams of primitive type are IntStream, LongStream and DoubleStream. In particular there is no BooleanStream and there is no idiomatic way to convert a Stream<Boolean> to a boolean[].

If you need this functionality frequently you can use a utility class like this:

public final class BooleanUtils {    private BooleanUtils() {}    public static boolean[] listToArray(List<Boolean> list) {        int length = list.size();        boolean[] arr = new boolean[length];        for (int i = 0; i < length; i++)            arr[i] = list.get(i);        return arr;    }    public static final Collector<Boolean, ?, boolean[]> TO_BOOLEAN_ARRAY         = Collectors.collectingAndThen(Collectors.toList(), BooleanUtils::listToArray);} 

Then, given a Stream<Boolean>, you will be able to do:

boolean[] arr = stream.collect(BooleanUtils.TO_BOOLEAN_ARRAY);

If you're not opposed to the idea of getting a list instead, you can simply perform collect as your terminal action:

final List<Boolean> boolList = Arrays.stream(array)                                     .map(Boolean.class::cast)                                     .map(Boolean::booleanValue)                                     .collect(Collectors.toList());

The stream as defined here is only capable of producing an Object[] if you attempt to collect it into an array. Using a list will at least allow you to maintain the type you want to convert it into.