Java Collections emptyMap() Method

The emptyMap() method of Java Collections class returns an empty map which is immutable.

Syntax

Following is the declaration of emptyMap() method:

Parameter

This method does not accept any parameter.

Returns

The emptyMap() method returns an empty immutable Map.

Exceptions

Compatibility Version

Java 1.5 and above

Example 1

import java.util.*;
public class CollectionsEmptyMapExample1 {
	public static void main(String[] args) {		
	     //Create an empty Map    
	     Map<String,String> EmptyMap = Collections.emptyMap();
	     System.out.println("Created Empty Map: "+EmptyMap);
	     }	  
}

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Output:

Created Empty Map: {}

Example 2

import java.util.*;
public class CollectionsEmptyMapExample2 {
	public static void main(String[] args) {		
	     //Create an empty Map   
	     Map<String,String> EmptyMap = Collections.emptyMap();
	     System.out.println("Created Empty Map: "+EmptyMap);
	     // try to add elements
	     EmptyMap.put("1","from JavaTpoint.com");
	     }	  
}

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Output:

Created Empty Map: {}
Exception in thread "main" java.lang.UnsupportedOperationException
	at java.base/java.util.AbstractMap.put(AbstractMap.java:209)
	at myPackage.CollectionsEmptyMapExample2.main(CollectionsEmptyMapExample2.java:9)

Example 3

import java.util.*;
public class CollectionsEmptyMapExample3 {
	public static void main(String[] args) {		
		//Create an empty Map    
	      Map<Integer, Integer> empMap = Collections.emptyMap();
	      empMap.put(1, 23424);
	      empMap.put(2, 65776);    
	      System.out.println("Created empty immutable Map: "+empMap);	     
	      }	  
}

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Output:

Exception in thread "main" java.lang.UnsupportedOperationException
	at java.base/java.util.AbstractMap.put(AbstractMap.java:209)
	at myPackage.CollectionsEmptyMapExample3.main(CollectionsEmptyMapExample3.java:7)

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