Question

Let’s propose that I have the following class

    Public MyClass{

    Date date;

    //Mutable getters and setters

    public Date getdate(){
    retrurn date;
    }

    public Date setdate(Date date)
    {date = date;}

    //Now immutable setter and Getters 

    public Date getImmutableDate{
    return new Date(date.getDate());
    }

    public void setImmutableDate(Date mydate)
    {
    date = new Date(mydate.getDate());
    }
 }

Is it good practice to use mutable getters and setters for Spring or Hibernate Framework and using Immutable setters and getters for my custom coding. What Im i afraid of is the following:

MyClass myclass = new MyClass();
//assuming that item date was initalized some how.
Date currentDate = myClass.getdate();
currentDate.setMonth( currentDate.getMonth() + 1 );

Now what has happened that I just changed the value of date variable inside myClass object and it might be prime root for bugs in system.

Am I correct?
Can I use immutable getters and setters for Spring/Hibernate as well?

Answer 1

Note that if you provide a mutable setter and getter, it will eventually be used by people. So that’s not a good option.

The question is not particularly related to spring and hibernate, but more to API design. Josh Bloch advises – “minimize mutability”. But that means you should use immutable objects, and not create instances each time an object is obtained.

The solution above is to use joda-time‘s DateTime object, which is immutable.