LongStream parallel() in Java

LongStream parallel() is a method in java.util.stream.LongStream. This method returns a parallel LongStream, i.e, it may return itself, either because the stream was already present, or because the underlying stream state was modified to be parallel.

LongStream parallel() is an intermediate operation. These operations are always lazy. Intermediate operations are invoked on a Stream instance and after they finish their processing, they give a Stream instance as output.

Syntax :

LongStream parallel()

Where, LongStream is a sequence of 
primitive long-valued elements and the function 
returns a parallel LongStream.

Below given are some examples to understand the function in a better way.
Example 1 :

// Java program to demonstrate working of
// LongStream parallel() on a given range
import java.util.*;
import java.util.stream.LongStream;

class GFG {

    // Driver code
    public static void main(String[] args)
    {
        // Creating a stream of longs
        LongStream stream = LongStream.range(5L, 12L);

        System.out.println("The corresponding "
                           + "parallel LongStream is :");
        stream.parallel().forEach(System.out::println);
    }
}

Output :

The corresponding parallel LongStream is :
9
8
11
10
6
5
7

Example 2 :

// Printing sequential stream for the
// same input as above example 1.
import java.util.*;
import java.util.stream.LongStream;

class GFG {

    // Driver code
    public static void main(String[] args)
    {
        LongStream stream = LongStream.range(5L, 12L);

        System.out.println("The corresponding "
                           + "sequential LongStream is :");
        stream.sequential().forEach(System.out::println);
    }
}

Output :

The corresponding sequential LongStream is :
5
6
7
8
9
10
11

Example 3 :

// Java program to show sorted output
// of parallel stream.
import java.util.*;
import java.util.stream.LongStream;

class GFG {

    // Driver code
    public static void main(String[] args)
    {
        // Creating a stream of longs
        LongStream stream = LongStream.of(3L, 4L, 1L, 5L,
                                          2L, 3L, 9L);

        System.out.println("The sorted parallel"
                           + " LongStream is :");
        stream.parallel().sorted().forEach(System.out::println);
    }
}

Output :

The sorted parallel LongStream is :
4
2
3
9
3
5
1