Having trouble writing a constructor for a object inside another class - object

Question

Please don't get mad, I am amiting this is help on my homework but I like to learn this and can't find it anywhere. I have looked for it and couldn't find anything like it, idk if I am looking in all the wrong places or for the wrong thing I have two other classes inside my code and having trouble creating another class with class objectives inside of it, I will show what I attempted and see if yall can please help me out. Also, I want to make sure I am using the keyword " this" right in my other two classes. She wanted us to use this in our program and the comments are what we are told to do:
public class Person
{
private String lastName;
private String firstName;
//default constructor
public Person()
{
lastName= null;
firstName = null;
}
//two-parameter constructor
public Person(String lastName, String firstName)
{
this.lastName=lastName;
this.firstName=firstName;
}
//copy constructor
public Person(Person object2)
{
this.lastName=object2.lastName;
this.firstName=object2.firstName;
}
// standard accessor method for each of the two fields
public String getLastName(String lastName)
{
lastName = this.lastName;
return lastName;
}
public String getFirstName(String firstName)
{
firstName = this.firstName;
return firstName;
}
public void setLastName(String lastName)
{
this.lastName=lastName;
}
public void setFirstName(String firstName)
{
this.firstName=firstName;
}
//mutator method for both fields—using standard mutator methods
public void setName(String lastName,String firstName)
{
this.lastName= lastName;
this.firstName = firstName;
}
//toString method
public String toString()
{
String str = “Last Name: “ + lastName + “\nFirst Name: “ + firstName;
return str;
}
//equals method
public boolean equals(Person name2)
{
boolean status;
if (this.lastName.equals(name2.lastName) && this.firstName.equals(name2.firstName))
status = true;
else
status = false;
return status;
}
//copy method
public Person copy()
{
Person copyObject = new Person(lastName, firstName);
return copyObject;
}
}
public class Date
{
private int month;
private int day;
private int year;
//default constructor
public Date()
{
this (0,0,0);
}
//three-parameter constructor
public Date(int month, int day, int year)
{
this.month = month;
this.day = day;
this.year = year;
}
//copy constructor
public Date(Date object2)
{
this (object2.month, object2.day, object2.year);
}
//standard accessor method for each field
public int getMonth(int month)
{
month = this.month;
return month;
}
public int getDay(int day)
{
day = this.day;
return day;
}
public int getYear(int year)
{
year = this.year;
return year;
}
//standard mutator method for each field
public void setMonth(int month)
{
this.month = month;
}
public void setDay(int day)
{
this.day = day;
}
public void setYear(int year)
{
this.year = year;
}
//mutator method for both fields—using standard mutator methods
public void setDate(int month, int day, int year)
{
this.month = month;
this.day = day;
this.year= year;
}
//toString method
public String toString()
{
String str = "Date:" + month+ " " + day + ", " + year;
return str;
}
//equals method
public boolean equals (Date object2)
{
boolean status;
if (this.month == object2.month && this.day == object2.day && this.year == object2.year)
status = true;
else
status = false;
return status;
}
//copy method
public Date copy()
{
Date copyObject = new Date(month, day, year);
return copyObject;
}
}
And this is what I have been trying for my other class and It shows an ERROR:
public class PersonalInfo
{
private Person name;
private Date birthday;
private int idNumber;
// the default constructor
public PersonalInfo()
{
Person name = new Person();
Date birthday = new Date();
this.idNumber = 0;
}
// A constructor that passes 6 parameters
public PersonalInfo(String lastName, String firstName, int month, int day, int year, int idNumber )
{
Person name = new Person(lastName, firstName);
Date birthday= new Date(month, day, year);
this.idNumber = idNumber;
}
}
Please help! And thank you for looking

Answer 1

Since you haven't specified the language or the error message, this is only a qualified guess. If this isn't the actual problem, provide more details.
public PersonalInfo()
{
Person name = new Person();
Date birthday = new Date();
this.idNumber = 0;
}
You are declaring new local variables name and birthday here, rather than using the class members. That means the class members never get initialized, and I suspect that's what the error is trying to tell you.
The right way to do this is to just refer directly to the variables:
this.name = new Person();
this.birthday = new Date();
or, since this is implied when there is no local variable or parameter with the same name:
name = new Person();
birthday = new Date();