Best approach for setting the values of Instance Variables

[Ravi Kiran Va]

Hi ,
Please suggest me as knowing what is the best approach ??

That is to set the values of Instance variables by using an Parameterized constructor as shown below :

public class Employee {
	private int age;

	public Employee(int age) {
		super();
		this.age = age;
	}

	public int getAge() {
		return age;
	}

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

}

Or by explicitly calling the Setter Methods as shown below :

Employee emp = new Employee();
emp.setAge(28);

What you suggest , please share your ideas .

Thanks in advnace .

[Dieter Quickfend]

I'd choose the first, given that the second will cause a compiler error.

[Christophe Verré]

It depends. The constructor can be used as a convenient way to set variables, or not prevent other classes from setting the value again via a setter. A problem arises when you have too many instance variables. Using a constructor to instantiate them all would look ugly and difficult to use. Also, using a constructor with parameters forces other classes to pass values when instantiating the class. This can be inconvenient, unless you have different kind of constructors, like a default constructor.

[Ravi Kiran Va]

Thank you .

[Wouter Oet]

Christophe Verré wrote: A problem arises when you have too many instance variables. Using a constructor to instantiate them all would look ugly and difficult to use.

That can solved by implementing a builder.

[Christophe Verré]

Wouter Oet wrote:

Christophe Verré wrote: A problem arises when you have too many instance variables. Using a constructor to instantiate them all would look ugly and difficult to use.

That can solved by implementing a builder.

For the reference, that's recommended in Effective Java.

[David Newton]

(And don't call super() if you're just extending Object -- there's no need for it, and it's misleading.)