Java Collections emptySet() Method

The emptySet() method of Java Collections class is used to get the Set that has no elements. These empty Set are immutable in nature.

Syntax

Following is the declaration of emptySet() method:

Parameter

This method does not accept any parameter.

Returns

The emptySet() method returns an empty immutable Set.

Exceptions

Compatibility Version

Java 1.5 and above

Example 1

import java.util.*;
public class CollectionsEmptySetExample1 {
	public static void main(String[] args) {		
	     //Create an empty Set   
	     Set<String> EmptySet = Collections.<String>emptySet();
	     System.out.println("Empty Set: "+EmptySet);
	     }	  
}

Test it Now

Output:

Empty Set: []

Example 2

import java.util.*;
public class CollectionsEmptySetExample2 {
	public static void main(String[] args) {		
		//Create an empty Set
	      Set<String> EmptySet = Collections.emptySet();
	      System.out.println("Created empty immutable Set: "+EmptySet);
	      //Try to add elements
	      EmptySet.add("A");
	      EmptySet.add("B");
	      }	  
}

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Output:

Created empty immutable Set: []
Exception in thread "main" java.lang.UnsupportedOperationException
	at java.base/java.util.AbstractCollection.add(AbstractCollection.java:267)
	at myPackage.CollectionsEmptySetExample2.main(CollectionsEmptySetExample2.java:10)

Example 3

import java.util.*;
public class CollectionsEmptySetExample3 {
	public static void main(String[] args) {		
		//Create an empty Set    
	      Set<Integer> empSet = Collections.emptySet();
	      empSet.add(1);
	      empSet.add(2);    
	      System.out.println("Created empty immutable Set: "+empSet);	     
	      }	  
}

Test it Now

Output:

Exception in thread "main" java.lang.UnsupportedOperationException
	at java.base/java.util.AbstractCollection.add(AbstractCollection.java:267)
	at myPackage.CollectionsEmptySetExample3.main(CollectionsEmptySetExample3.java:8)

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