Question on HashSet

[wong sheena]

 import java.util.*;
 
public class Group extends HashSet <Person>{
 
public static void main(String args[]){
 
Group g = new Group();
g.add(new Person("Hana"));
g.add(new Person("Lotte"));
g.add(new Person("Jane"));
g.add(new Person("Hana"));
g.add(new Person("Jane"));

System.out.println("Total "+g.size());
 
for(Person buffer:g)
System.out.println(buffer);
}

public boolean add(Person o){

System.out.println("Adding:"+o);
return super.add(o);
}
}
 
class Person{

private String name;
 
Person(String name){
this.name =name;
}

public String toString(){

return name;
}
 
public boolean equals(Object o){

if((o instanceof Person)&&(this.name==((Person)o).name))
return true;
else
return false;

}
public int harshCode()
{
return 4;
} 
}
   

This is a Question from K & B pg 630.
I'm wondering why duplicate entry is allowed.
At first I thought it is because of the equals() and hashCode().I have added as well. Have I left out something??
Thanks in advance!

[Meena R. Krishnan]

First, change harshCode() to hashcode().

Then print out the returns of add() to see the duplicate ones are failing.

 
System.out.println(g.add(new Person("Hana")));
System.out.println(g.add(new Person("Lotte")));
System.out.println(g.add(new Person("Jane")));
System.out.println(g.add(new Person("Hana")));
System.out.println(g.add(new Person("Jane")));

I get the following result:

Adding:Hana
true
Adding:Lotte
true
Adding:Jane
true
Adding:Hana
false
Adding:Jane
false
Total 3
Jane
Lotte
Hana

[wong sheena]

First, change harshCode() to hashcode().

YeaH should be hashCode(). hehe.. Thanks