Question

I am doing some basic Java programming where i have to create classes which have constructors linked to other class constructors. For example, refer to my following code…

public class Friend {

    private String name;
    private Date dateOfBirth;
    private String phoneNum;

    public Friend(String name){
        this.name=name;
        this.dateOfBirth = null;
    }

    public Date setDOB(Date input){
        return dateOfBirth;
    }
}

public class Date {

    final int MINDAYSINMONTH=1; 
    final int MAXDAYSINMONTH=30;
    final int MINMONTHSINYEAR=1; 
    final int MAXMONTHSINYEAR=12;
    private int day;
    private int month;
    private int year;

    //constructor
    public Date(int day, int month, int year){
        this.day=day;
        this.month=month;
        this.year=year;
    }
}

I am trying to create a new Friend, then alter the dateOfBirth value that is within the Friend class, like so…

Friend trial = new Friend(input);
trial.setDOB(new Date(2, 15, 1991));

But my output suggests that i have created a new Friend but the dateOfBirth didn’t change to the values that I supplied above. Could someone please help me understand what I’m doing wrong.

Answer 1

Your setDOB method is wrong – it isn’t actually setting anything at all.

Try changing this…

public void setDOB(Date input){
    this.dateOfBirth = input;
}

You should probably also have a getter method so you can check the value after it has been set…

public Date getDOB(){
    return dateOfBirth;
}