Initialize a static Map using Stream in Java

In this article, a static map is created and initialised in Java using Stream.

Static Map in Java
A static map is a map which is defined as static. It means that the map becomes a class member and can be easily used using class.

Stream In Java
Introduced in Java 8, the Stream API is used to process collections of objects. A stream is a sequence of objects that supports various methods which can be pipelined to produce the desired result.



Approach:

  • Create a stream and insert 2D values as Key and Value pair in it.
  • These values will be later used to instantiate the Map.
  • Using the collect() method of Stream, map the values from the stream to the map.
  • This can be done with the help of Collectors.toMap() method and the keyMapper and ValueMapper respectively.

Below is the implementation of the above approach:

filter_none

edit
close

play_arrow

link
brightness_4
code

// Java program to create a static map using Stream
  
import java.util.*;
import java.util.stream.Collectors;
  
class GFG {
  
    // Declaring and instantiating the static map
    private static Map<String, String> map
        = Arrays.stream(new String[][] {
                            { "1", "GFG" },
                            { "2", "Geek" },
                            { "3", "GeeksForGeeks" } })
              .collect(Collectors.toMap(
                  keyMapper -> keyMapper[0], valueMapper -> valueMapper[1]));
  
    // Driver code
    public static void main(String[] args)
    {
        System.out.println(map);
    }
}

chevron_right


Output:

{1=GFG, 2=Geek, 3=GeeksForGeeks}



My Personal Notes arrow_drop_up

Check out this Author's contributed articles.

If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.

Please Improve this article if you find anything incorrect by clicking on the "Improve Article" button below.


Article Tags :
Practice Tags :


Be the First to upvote.


Please write to us at contribute@geeksforgeeks.org to report any issue with the above content.