// concurrent/ParallelStreamPuzzle.java
import java.util.*;
import java.util.function.*;
import java.util.stream.*;
public class ParallelStreamPuzzle {
    static class IntGenerator
    implements Supplier<Integer> {
        private int current = 0;
        @Override
        public Integer get() {
            return current++;
        }
    }
    public static void main(String[] args) {
        List<Integer> x = Stream.generate(newIntGenerator())
        .limit(10)
        .parallel()  // [1]
        .collect(Collectors.toList());
        System.out.println(x);
    }
}