Saturday, January 24, 2026
HomeLanguagesJavaSets union() function | Guava | Java

Sets union() function | Guava | Java

Guava’s Sets.union() returns an unmodifiable view of the union of two sets. The returned set contains all elements that are contained in either backing set. Iterating over the returned set iterates first over all the elements of set1, then over each element of set2, in order, that is not contained in set1.

Syntax:

public static <E> 
  Sets.SetView<E> 
    union(Set<? extends E> set1, 
          Set<? extends E> set2)

Return Value: This method returns an unmodifiable view of the union of two sets.

Example 1:




// Java code to show implementation
// of Guava's Sets.union() method
  
import com.google.common.collect.Sets;
import java.util.Set;
  
class GFG {
  
    // Driver's code
    public static void main(String[] args)
    {
        // Creating first set
        Set<Integer>
            set1 = Sets.newHashSet(1, 2, 3, 4, 5);
  
        // Creating second set
        Set<Integer>
            set2 = Sets.newHashSet(3, 5, 7, 9);
  
        // Using Guava's Sets.union() method
        Set<Integer>
            answer = Sets.union(set1, set2);
  
        // Displaying the union of set set1 and set2
        System.out.println("Set 1: "
                           + set1);
        System.out.println("Set 2: "
                           + set2);
        System.out.println("Set 1 union Set 2: "
                           + answer);
    }
}


Output:

Set 1: [1, 2, 3, 4, 5]
Set 2: [9, 3, 5, 7]
Set 1 union Set 2: [1, 2, 3, 4, 5, 9, 7]

Example 2:




// Java code to show implementation
// of Guava's Sets.union() method
  
import com.google.common.collect.Sets;
import java.util.Set;
  
class GFG {
  
    // Driver's code
    public static void main(String[] args)
    {
        // Creating first set
        Set<String>
            set1 = Sets.newHashSet("G", "e", "e", "k", "s");
  
        // Creating second set
        Set<String>
            set2 = Sets.newHashSet("g", "f", "G", "e");
  
        // Using Guava's Sets.union() method
        Set<String>
            answer = Sets.union(set1, set2);
  
        // Displaying the union of set set1 and set2
        System.out.println("Set 1: "
                           + set1);
        System.out.println("Set 2: "
                           + set2);
        System.out.println("Set 1 union Set 2: "
                           + answer);
    }
}


Output:

Set 1: [k, s, e, G]
Set 2: [e, f, g, G]
Set 1 union Set 2: [k, s, e, G, f, g]
Dominic
Dominichttp://wardslaus.com
infosec,malicious & dos attacks generator, boot rom exploit philanthropist , wild hacker , game developer,
RELATED ARTICLES

2 COMMENTS

Most Popular

Dominic
32475 POSTS0 COMMENTS
Milvus
122 POSTS0 COMMENTS
Nango Kala
6847 POSTS0 COMMENTS
Nicole Veronica
11977 POSTS0 COMMENTS
Nokonwaba Nkukhwana
12065 POSTS0 COMMENTS
Shaida Kate Naidoo
6986 POSTS0 COMMENTS
Ted Musemwa
7221 POSTS0 COMMENTS
Thapelo Manthata
6934 POSTS0 COMMENTS
Umr Jansen
6912 POSTS0 COMMENTS