The java.util.IdentityHashMap.entrySet() method in Java is used to create a set out of the same elements contained in the map. It basically returns a set view of the identity hash map or we can create a new set and store the map elements into them.
Syntax:
Identity_HashMap.entrySet()
Parameters: The method does not take any parameter.
Return Value: The method returns a set having same elements as the map.
Below programs illustrate the java.util.IdentityHashMap.entrySet() Method:
Program 1: Mapping String Values to Integer Keys.
// Java code to illustrate the entrySet() method import java.util.*;   public class Identity_Hash_Map_Demo {     public static void main(String[] args)     {           // Creating an empty IdentityHashMap         IdentityHashMap<Integer, String> identity_hash =                       new IdentityHashMap<Integer, String>();           // Mapping string values to int keys         identity_hash.put( 10 , "Geeks" );         identity_hash.put( 15 , "4" );         identity_hash.put( 20 , "Geeks" );         identity_hash.put( 25 , "Welcomes" );         identity_hash.put( 30 , "You" );           // Displaying the IdentityHashMap         System.out.println( "Initial Mappings are: " +                                              identity_hash);           // Using entrySet() to get the set view         System.out.println( "The set is: " +                                    identity_hash.entrySet());     } } |
Initial Mappings are: {10=Geeks, 30=You, 20=Geeks, 25=Welcomes, 15=4} The set is: [10=Geeks, 30=You, 20=Geeks, 25=Welcomes, 15=4]
Program 2: Mapping Integer Values to String Keys.
// Java code to illustrate the entrySet() method import java.util.*;   public class Identity_Hash_Map_Demo {     public static void main(String[] args)     {           // Creating an empty IdentityHashMap         IdentityHashMap<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( "Initial Mappings are: " +                                                identity_hash);           // Using entrySet() to get the set view         System.out.println( "The set is: " +                                    identity_hash.entrySet());     } } |
Initial Mappings are: {Geeks=20, Welcomes=25, You=30, 4=15} The set is: [Geeks=20, Welcomes=25, You=30, 4=15]
Note: The same operation can be performed with any type of Mappings with variation and combination of different data types.