Stream of Function[]

how can i use Stream for Function[]? My solution looks very ugly plus i know that this can be done by using reduce().

class A {   
    static void run() {
        Integer a = applyConversions(3, x -> x * 3, x -> x + 4);                  // output: 13

        String b = applyConversions("One", s -> "Two " + s, String::toUpperCase); // output: OneTwo
    }

    static <T> T applyConversions(T value, Function<T, T>... conversions) {
        /*
        todo: apply each conversion function to 'value'

        ==>My Ugly solution<==
        final Object[] valueHelper = {null};
        valueHelper[0] = value;
        Stream.of(conversions).forEach(s-> valueHelper[0] = s.apply((T)valueHelper[0]));
        return (T)valueHelper[0];
        */
        return value;
    }
}

I can change only signature and body of 'applyConversions' method

You seem to want to reduce the functions using andThen. Assuming conversions can't be empty, you can do:

static <T> T applyConversions(T value, Function<T, T>... conversions) {
    return Arrays.stream(conversions).reduce(Function::andThen).get().apply(value);
}

If it can be empty, you need to decide what to return when it is empty.

return Arrays.stream(conversions).reduce(Function::andThen)
        .map(x -> x.apply(value)).orElse(someDefaultValue);

If you want it to use value as the default value, you do orElse(Function.identity()) instead of getting the optional.

return Arrays.stream(conversions)
   .reduce(Function::andThen).orElse(Function.identity())
   .apply(value);