hashCode method implementation

[wrushasen dakhane]

Consider we have

Employee e1 = new Employee("TCS");
Employee e2 = new Employee("GS");
Employee e3 = new Employee("TCS");

where Employee is our class.

How should we implement the hashCode method so that we can have same hasCode value for objects e1 and e3.
Best Regards,
Wrushasen D.

[Nitesh Kant]

In your hashcode method, return the hashcode() for the field that stores the employee name or whatever "TCS"/"GS" stands for. eg:

   
    public int hashCode() {
        return (empName != null ? empName.hashCode() : 0);
    }
 

Also, in your equals method you should only test for the equality of the employee name in this case. So, that your equals and hashCode methods are consistent. eg:

    
    public boolean equals(Object o) {
        if(this == o) {
            return true;
        }
        if(o == null || getClass() != o.getClass()) {
            return false;
        }
 
        final Employee that = (Employee) o;
 
        return !(empName != null ? !empName.equals(that.empName) : that.empName != null);
 
    }