A serious question ,could someone help me please just a little problem

Question

this is a program to let me open a file and read birthday and related name, and then type name we can fetch the birthday, everything is ok ,whenever i input a name, it always find nothing, can some experts help me please
there are three class i defined, one is birth_reader, another is date to record the date have been read from specified file, one is the name stored firstname and last name, the file my lecture give me is just a simple txt file which is example like:
1 31 1984 robin ralu
i realised maybe i shoud add a equals() to test ,but how can i do that , i have really no idea
please
import java.util.Scanner.*;
import java.util.*;
import java.io.*;
public class birth_reader
public static void main(String[] args)throws IOException
birth_reader haha=new birth_reader();
Map <name,date> book=new HashMap<name,date>();
Scanner input=new Scanner(System.in);
name b;
FileReader fin = new FileReader("birthday.txt");
Scanner sc = new Scanner(fin);
while(sc.hasNext())
int cat=sc.nextInt();
int cta=sc.nextInt();
int atc=sc.nextInt();
String first_name=sc.next();
String last_name=sc.next();
date a=new date(cat,cta,atc);
b=new name(first_name,last_name);
book.put(b,a);
System.out.println(book);
System.out.println("please enter the name");
String f=input.next();
String l=input.next();
b.firstname=f;
b.lastname=l;
date p=book.get(b);
if((p!=null))
System.out.println(b+":"+p);
else{ System.out.println("no person here"+" "+b);
public class name
String firstname,lastname;
public name(String firstname,String lastname)
this.firstname=firstname;
this.lastname=lastname;
public String toString()
return firstname+" "+lastname;
public class date
int year,month,day;
public date(int year,int month,int day)
this.year=year;
this.month=month;
this.day=day;
public String toString()
return year+" "+month+" "+day;
public int getyear()
return year;
public int getmonth()
return month;
public int getday()
return day;
}

Answer 1

Why do you suppose you should add an equals method?
In what class would you add it?
How would that change the behaviour of your code?
What else should you keep in mind when overriding equals?