Question about hashSet

[Sammy Bill]

  public class Student {
	private String name;
	 public Student(String name) {
	 this.name = name;
	 }
	 public boolean equals(Object o) {
	 if( !(o instanceof Student) ) return false;
	 Student p = (Student) o;
	 return p.name.equals(this.name);
	 }
	 public static void main(String [] args) {
		 HashSet<Student> set = new HashSet<Student>();
		 set.add(new Student("oussama"));
		 set.add(new Student("oussama"));
		 System.out.print(set.size());
	 }
	 }  

i was expecting this code to return 1 as i overrode equals. but it returned 2?
why is that?

Thanks

[Henry Wong]

i was expecting this code to return 1 as i overrode equals. but it returned 2?
why is that?

The hashing collections require that you to obey the equal() / hashCode() contract. If you override equals, then you should also override hashCode() as well -- as you have the code written, you broke the contract.

Henry

[Ankit Garg]

hashCode method is not overridden. So equals will not get called. So answer will be 2...

[Abhi vijay]

This is because you have not overridden hashCode().

[Sammy Bill]

Thanks

Got it.