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.