Challenges

Remember the rules for this are

• Try to use only the information given up to this point in this book.
• Try not to give up until you've given it a solid attempt

Challenge 1.

Translate the following code using a for-loop to code using streams.

import module java.base;

class Main {
    void main() {
        List<Integer> numbers = List.of(0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10);
        for (int n : numbers) {
            IO.println(n);
        }
    }
}

Challenge 2.

Translate the following code using a for-loop to code using streams.

import module java.base;

class Main {
    void main() {
        List<Integer> timestamps = List.of(1, 1756137441);

        Set<Instant> instants = new HashSet<>();
        for (int timestamp : timestamps) {
            instants.add(Instant.ofEpochSecond(timestamp));
        }

        IO.println(instants);
    }
}

Challenge 3.

Read the documentation on Collector and Collectors.

Make an implementation of Collector that can collect elements into MySpecialList.

import module java.base;

class MySpecialList<T> extends ArrayList<T> {}

class Main {
    // CODE HERE

    void main() {
        MySpecialList<Integer> l = Stream.of(1, 2, 3)
            .collect(/* CODE HERE */);
    }
}