In this article, a static map is created and initialized 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:
// 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); }} |
Output:
{1=GFG, 2=Geek, 3=GeeksForGeeks}