HashMapDemo.java

public class Employee{
  
    private int id;
    private String employeeName;
 
    public Employee(int id) {
        this.id= id;
    }
 
    //getters and setters
 
    @Override
    public int hashCode() {
        final int prime = 31;
        int result = 1;
        result = prime * result + id;  
        return result;
    }
 
    @Override
    public boolean equals(Object obj) {
        if (this == obj)
            return true;
        if (obj == null)
            return false;
        if (getClass() != obj.getClass())
            return false;
        Employee other = (Employee) obj;
        if (id!= other.id)
            return false;
        return true;
    }