Custom object without implement the hashcode and equals methods store into HashMap
package com.test.model; import java.util.HashMap; import java.util.Map; /*** * custom object without implement the hashcode and equals used in the Hashmap * This program used to how custom object handle in HashMap * @author Prakash * */ public class HashMapTest { public static void main(String[] args) { // TODO Auto-generated method stub Map<Employee,Employee> map = new HashMap<>(); Employee e1 = new Employee(1,"Senthil"); Employee e2 = new Employee(1,"Senthil"); /** * write e1 custom object store to hashmap * without override the hashcode and equals method * output * put(e1,e1) : null * because of this the first entry in the map * **/ System.out.println("put(e1,e1) : " + map.put(e1,e1)); /*** * Get the e1 object and print * Output * get(e1) : id :1 name:Senthil * e1 reference pointing to same object which added in the hashmap * hence e1 object