The java.util.IdentityHashMap.isEmpty() method of IdentityHashMap class is used to check for the emptiness of the map. The method returns True if no key-value pair or mapping is present in the map else False.
Syntax:
Identity_Hash_Map.isEmpty()
Parameters:
The method does not take any parameters.
Return Value:
The method returns a boolean true if the map is empty or does not contain any mapping pairs else boolean false. The below programs illustrate the working of java.util.IdentityHashMap.isEmpty() method:
Program 1:
Mapping String Values to Integer Keys.
// Java code to illustrate the isEmpty() method import java.util.*;
public class Identity_Hash_Map_Demo {
public static void main(String[] args)
{
// Creating an empty IdentityHashMap
Map<String, Integer> identity_hash = new IdentityHashMap<String, Integer>();
// Mapping int values to string keys
identity_hash.put( "Geeks" , 10 );
identity_hash.put( "4" , 15 );
identity_hash.put( "Geeks" , 20 );
identity_hash.put( "Welcomes" , 25 );
identity_hash.put( "You" , 30 );
// Displaying the IdentityHashMap
System.out.println( "The Mappings are: " +
identity_hash);
// Checking for the emptiness of Map
System.out.println( "Is the map empty? " +
identity_hash.isEmpty());
}
} |
The Mappings are: {Geeks=20, Welcomes=25, You=30, 4=15} Is the map empty? false
Program 2:
For an empty IdentityHashMap
// Java code to illustrate the isEmpty() method import java.util.*;
public class Identity_Hash_Map_Demo {
public static void main(String[] args)
{
// Creating an empty IdentityHashMap
Map<String, Integer> identity_hash = new IdentityHashMap<String, Integer>();
// Displaying the IdentityHashMap
System.out.println( "The Mappings are: " +
identity_hash);
// Checking for the emptiness of Map
System.out.println( "Is the map empty? " +
identity_hash.isEmpty());
}
} |
The Mappings are: {} Is the map empty? true
Note:
The same operation can be performed with any type of Mappings with variation and combination of different data types. All methods of Java.util.IdentityHashMap Class