Convert a Set to Stream in Java

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Set interface extends Collection interface and Collection has stream() method that returns a sequential stream of the collection. Below given are some examples to understand the implementation in a better way. Example 1 : Converting Integer HashSet to Stream of Integers.

Java

// Java code for converting
// Set to Stream
import java.util.*;
import java.util.stream.Stream;
 
class GFG {
     
    // Driver code
    public static void main(String[] args) {
     
    // Creating an Integer HashSet
    Set<Integer> set = new HashSet<>();
     
    // adding elements in set
    set.add(2);
    set.add(4);
    set.add(6);
    set.add(8);
    set.add(10);
    set.add(12);
     
    // converting Set to Stream
    Stream<Integer> stream = set.stream();
     
    // displaying elements of Stream using lambda expression
    stream.forEach(elem->System.out.print(elem+" "));
     
    }
}

Output:

2 4 6 8 10 12

Example 2 : Converting HashSet of String to stream.

Java

// Java code for converting
// Set to Stream
import java.util.*;
import java.util.stream.Stream;
 
class GFG {
     
    // Driver code
    public static void main(String[] args) {
     
    // Creating an String HashSet
    Set<String> set = new HashSet<>();
     
    // adding elements in set
    set.add("Geeks");
    set.add("for");
    set.add("GeeksQuiz");
    set.add("Lazyroar");
     
    // converting Set to Stream
    Stream<String> stream = set.stream();
     
    // displaying elements of Stream
    stream.forEach(elem -> System.out.print(elem+" "));
     
    }
}

Output:

Lazyroar Geeks for GeeksQuiz

Note : Objects that you insert in HashSet are not guaranteed to be inserted in same order. Objects are inserted based on their hash code. Convert Stream to Set in Java