Styjun

My professor gave us this homework exercise and has created a project with
a bunch of unit tests.
Our goal is to make sure we can pass those unit tests.
We have three classes.
A class called Person with a name and an age,
a class Speaker that extends Person,
and a class Attendee that also extends Person.
I am struggling with making sure that there are no duplicate people. generateRandomString() was implemented by the professor and just returns a random string.

I already created the class,
it's constructor,
getters,
and setters.
I also overrode the method equals() in the class Person

This is the test our professor gave us:

 @Test
 public void testNoDuplicatePerson() 
 HashSet<Person> people = new HashSet<Person>();
 String name = generateRandomString();
 Person p = new Speaker(name);
 people.add(p);
 assertEquals(1,people.size());
 p = new Attendee(name);
 people.add(p);
 assertEquals(1,people.size());
 

How can I pass this test?

EDIT: I decided to post the code of the three classes:

Person
 ```java
public abstract class Person 
 private String name;
 private int age;

 public Person(String name) 
 this.name = name;
 this.age = 0;
 

 public Person(String name, int age) 
 this.name = name;
 this.age = age;
 

 public String getName() 
 return name;
 

 public void setName(String name) 
 this.name = name;
 

 public int getAge() 
 return age;
 

 public void setAge(int age) 
 this.age = age;
 

 public boolean equals(Object o) 
 if (o == null 

Speaker:

public class Speaker extends Person 

 private int fee;

 public Speaker(String name) 
 super(name);
 this.fee = 0;
 

 public Speaker(String name, int age) 
 super(name, age);
 this.fee = 0;
 

 public Speaker(String name, int age, int fee) 
 super(name, age);
 this.fee = fee;
 

 public int getFee() 
 return fee;
 

 public void setFee(int fee) 
 this.fee = fee;
 

 public String toString() 
 return "Speaker " + this.getName() + " as a fee value of " + this.getFee() + ".";
 

Attendee:

public class Attendee extends Person 
 private boolean paid;

 public Attendee(String name) 
 super(name);
 this.paid=false;
 

 public Attendee(String name, int age) 
 super(name, age);
 this.paid=false;
 

 public boolean hasPaid()
 if (this.paid==true)
 return true;
 return false;
 
 public String toString()
 return "Attendee "+this.getName()+(this.hasPaid() ? " has":" hasn't")+" paid its registration.";
 

As mentioned by @JB Nizet, when you override the equals method of a class,
you must override the hashCode method.
Note the name of the class in the jUnit test: HashSet.
That depends on the hashCode method.
Solution:

a. Learn to read the java API docs.
Here is a link to the v8 JavaDocs.
Read the HashSet page.

b. Implement the hashCode method.
You clearly have Internet access,
so, if you don't know how to implement a hashCode method,
try a google search for "how do I implement a Java hashCode method".

Hint: String already implements a hashCode method.