The java.util.IdentityHashMap.hashCode() method in Java is used to fetch the hash code value of a particular this IdentityHashMap. A map consists of a number of buckets to store the key-value pair. Each bucket has a unique identity and when a key-value pair is inserted into a bucket, the key’s hashcode is matched with the identifier of the bucket, and if its a match the pair is stored successfully. This is how the hash code works.
Syntax:
Identity_HashMap.hashCode()
Parameters: The method does not accept any parameters.
Return Value: The method returns the hashcode value of the map.
Below programs are used to illustrate the working of java.util.IdentityHashMap.hashCode() Method:
Program 1: Mapping String Values to Integer Keys.
// Java code to illustrate the hashCode() 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); // Getting the hashcode value for the map System.out.println("The hashcode value of the map: " + identity_hash.hashCode()); } } |
Initial Mappings are: {10=Geeks, 30=You, 20=Geeks, 25=Welcomes, 15=4}
The hashcode value of the map: 2043437408
Program 2: Mapping Integer Values to String Keys.
// Java code to illustrate the hashCode() 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("Initial Mappings are: " + identity_hash); // Getting the hashcode value for the map System.out.println("The hashcode value of the map: " + identity_hash.hashCode()); } } |
Initial Mappings are: {Geeks=20, Welcomes=25, You=30, 4=15}
The hashcode value of the map: 751311572
Note: The same operation can be performed with any type of Mapping with variation and combination of different data types.
Attention reader! Don’t stop learning now. Get hold of all the important Java Foundation and Collections concepts with the Fundamentals of Java and Java Collections Course at a student-friendly price and become industry ready.
