why below code returning set size as 5? even though hashcode and equals method is overridden it should return set size as 3

Question

//why output of this code is 5 instead of 3 //why output of this code is 5 instead of 3 //why output of this code is 5 instead of 3//why output of this code is 5 instead of 3

public class Dummy {

    public static void main(String[] args) {

        Set set = new HashSet();

        set.add(new Student("abc"));

        set.add(new Student("abcd"));

        set.add(new Student("abc"));

        set.add(new Student("abc"));

        set.add(new Student("abcdef"));

        System.out.println(set.size());

    }
}

class Student
{
    private String age;

    public Student(String age)
    {
        this.age=age;
    }

    public boolean equals(Student stu)

    {
        System.out.println("equals from Student parameter called");
        return false;
    }

    public boolean equals(Object obj)

    {
        System.out.println("equals from Object parameter called");

        return true;
    }

    public int hashcode()

    {
        System.out.println("hashcode called");

        return 17;

    }
}

Answer 1

It's not supposed to be public int hashcode(), it's public int hashCode(), so you've only overridden equals(). There may still be "equal" (based on your implementation) objects in different buckets since they don't all get same hash.

The @Override annotation is very helpful in these kinds of cases.