Java Collections unmodifiableSet() Method with Examples

by Online Tutorials Library July 22, 2022

Java Collections unmodifiableSet() Method

The unmodifiableSet() method of Java Collections class is used to get an unmodifiable view of the specified set.

Syntax

Following is the declaration of unmodifiableSet() method:

Parameter

Parameter	Description	Required/Optional
s	It is the set for which an unmodifiable view is to be returned.	Required

Returns

The unmodifiableSet() method returns an unmodifiable view of the specified set.

Exceptions

Example 1

  import java.util.*;  public class CollectionsUnmodifiableSetExample1 {  public static void main(String[] args) {  Set<Integer> set = new TreeSet<>();              Collections.addAll(set, 1,2,3,4,5);              System.out.println(“Initial Set: ” + set);              Set<Integer> set2 = Collections.unmodifiableSet(set);              System.out.println(“Unmodifiable Set: ” + set2);              //Modifying the original set              set.add(15);              System.out.println(“Unmodifiable Set: ” + set2);        }  }  

Test it Now

Output:

Initial Set: [1, 2, 3, 4, 5]  Unmodifiable Set: [1, 2, 3, 4, 5]  Unmodifiable Set: [1, 2, 3, 4, 5, 15]

Example 2

  import java.util.*;  public class CollectionsUnmodifiableSetExample2 {  public static void main(String[] args) {  Set<String> set = new TreeSet<>();              Collections.addAll(set, “Google”, “Facebook”, “Instagram”);              System.out.println(“Initial Set: ” + set);              Set<String> set2 = Collections.unmodifiableSet(set);              System.out.println(“Unmodifiable Set: ” + set2);              //Modifying the original set              set.add(“Twitter”);              System.out.println(“Unmodifiable Set: ” + set2);        }  }  

Test it Now

Output:

Initial Set: [Facebook, Google, Instagram]  Unmodifiable Set: [Facebook, Google, Instagram]  Unmodifiable Set: [Facebook, Google, Instagram, Twitter]

Example 3

  import java.util.*;  public class CollectionsUnmodifiableSetExample3 {  public static void main(String[] args) {  Set<Integer> set = new TreeSet<>();              Collections.addAll(set, 11, 13, 17);              System.out.println(“Original Set: ” + set);              Set<Integer> set2 = Collections.unmodifiableSet(set);              set2.add(19);        }  }  

Test it Now

Output:

Original Set: [11, 13, 17]  Exception in thread "main" java.lang.UnsupportedOperationException  at java.base/java.util.Collections$UnmodifiableCollection.add(Collections.java:1056)  at myPackage.CollectionsUnmodifiableSetExample3.main(CollectionsUnmodifiableSetExample3.java:9)

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Java Collections unmodifiableSet() Method with Examples

Java Collections unmodifiableSet() Method

Syntax

Parameter

Returns

Exceptions

Example 1

Example 2

Example 3

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