import java.util.ArrayList;
import java.util.List;
import java.util.stream.Stream;

/**
 * 
 * To enable parallelism, all you have to do is to create a parallel
 * stream, instead of sequential stream. And to surprise you, this is
 * really very easy.
 * 
 * Anytime you want to particular job using multiple threads in
 * parallel cores, all you have to call method parallelStream() method
 * instead of stream() method.
 *
 */
public class StreamDemo
{
    public static void main(String[] args)
    {
        List<Integer> numberList = new ArrayList<Integer>();
        
        for (int i = 1; i < 20; i++)
        {
            numberList.add(i);
        }
        
        // Here creating a parallel stream
        Stream<Integer> parallelStream = numberList.parallelStream();
        Integer[] evenNumbersArray = parallelStream.filter(i -> i % 2 == 0)
                                                   .toArray(Integer[]::new);
        
        for (Integer evenNumber : evenNumbersArray)
        {
            System.out.println(evenNumber);
        }
    }
}

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