- Java.util Package Classes
- Java.util - Home
- Java.util - ArrayDeque
- Java.util - ArrayList
- Java.util - Arrays
- Java.util - BitSet
- Java.util - Calendar
- Java.util - Collections
- Java.util - Currency
- Java.util - Date
- Java.util - Dictionary
- Java.util - EnumMap
- Java.util - EnumSet
- Java.util - Formatter
- Java.util - GregorianCalendar
- Java.util - HashMap
- Java.util - HashSet
- Java.util - Hashtable
- Java.util - IdentityHashMap
- Java.util - LinkedHashMap
- Java.util - LinkedHashSet
- Java.util - LinkedList
- Java.util - ListResourceBundle
- Java.util - Locale
- Java.util - Observable
- Java.util - PriorityQueue
- Java.util - Properties
- Java.util - PropertyPermission
- Java.util - PropertyResourceBundle
- Java.util - Random
- Java.util - ResourceBundle
- Java.util - ResourceBundle.Control
- Java.util - Scanner
- Java.util - ServiceLoader
- Java.util - SimpleTimeZone
- Java.util - Stack
- Java.util - StringTokenizer
- Java.util - Timer
- Java.util - TimerTask
- Java.util - TimeZone
- Java.util - TreeMap
- Java.util - TreeSet
- Java.util - UUID
- Java.util - Vector
- Java.util - WeakHashMap
- Java.util Package Extras
- Java.util - Interfaces
- Java.util - Exceptions
- Java.util - Enumerations
- Java.util Useful Resources
- Java.util - Useful Resources
- Java.util - Discussion
Java Collections unmodifiableSet() Method
Description
The Java Collections unmodifiableSet() method Returns an unmodifiable view of the specified set.
Declaration
Following is the declaration for java.util.Collections.unmodifiableSet() method.
public static <T> boolean addAll(Collection<? super T> c, T.. a)
Parameters
s − This is the set for which an unmodifiable view is to be returned.
Return Value
The method call returns an unmodifiable view of the specified set.
Exception
NA
Getting Immutable Set From a Mutable Set of Integer Example
The following example shows the usage of Java Collection unmodifiableSet(Set) method. We've created a Set object of Integer. Few entries are added and then using unmodifiableSet(Set) method, we've retrieved the immutable version of set and printed the set.
package com.tutorialspoint; import java.util.Collections; import java.util.HashSet; import java.util.Set; public class CollectionsDemo { public static void main(String[] args) { // create set Set<Integer> set = new HashSet<Integer>(); // populate the set set.add(1); set.add(2); set.add(3); // create a immutable set Set<Integer> immutableSet = Collections.unmodifiableSet(set); System.out.println("Immutable set is :"+immutableSet); } }
Output
Let us compile and run the above program, this will produce the following result.
Immutable set is :[1, 2, 3]
Getting Immutable Set From a Mutable Set of String Example
The following example shows the usage of Java Collection unmodifiableSet(Set) method. We've created a Set object of String and String. Few entries are added and then using unmodifiableSet(Set) method, we've retrieved the immutable version of map and printed the map.
package com.tutorialspoint; import java.util.Collections; import java.util.HashSet; import java.util.Set; public class CollectionsDemo { public static void main(String[] args) { // create set Set<String> set = new HashSet<String>(); // populate the set set.add("TP"); set.add("IS"); set.add("BEST"); // create a immutable set Set<String> immutableSet = Collections.unmodifiableSet(set); System.out.println("Immutable set is :"+immutableSet); } }
Output
Let us compile and run the above program, this will produce the following result.
Immutable set is :[IS, BEST, TP]
Getting Immutable Set From a Mutable Set of Object Example
The following example shows the usage of Java Collection unmodifiableSet(Set) method. We've created a Set object of String and Student object. Few entries are added and then using unmodifiableSet(Set) method, we've retrieved the immutable version of map and printed the map.
package com.tutorialspoint; import java.util.Collections; import java.util.HashSet; import java.util.Set; public class CollectionsDemo { public static void main(String[] args) { // create set Set<Student> set = new HashSet<Student>(); // populate the set set.add(new Student(1, "Julie")); set.add(new Student(2, "Robert")); set.add(new Student(3, "Adam")); // create a immutable set Set<Student> immutableSet = Collections.unmodifiableSet(set); System.out.println("Immutable set is :"+immutableSet); } } class Student { int rollNo; String name; Student(int rollNo, String name){ this.rollNo = rollNo; this.name = name; } @Override public String toString() { return "[ " + this.rollNo + ", " + this.name + " ]"; } }
Output
Let us compile and run the above program, this will produce the following result.
Immutable set is :[[ 1, Julie ], [ 2, Robert ], [ 3, Adam ]]
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