Thread: What difference does an additional constructor make to your program?

Hi, I'm just wondering what benefit a parameterized constructor (other than giving the option of overloading the default constructor)? If I had a default constructor along with getters and setters, what would be the point of also having a parameterized constructor?

package business;
 
import java.text.NumberFormat;
 
public class Pokemon {
 
	//the instance variables
	private String name;
	private String type;
	private double price;
 
	//the default constructor
	public Pokemon(){
		name = "";
		type = "";
		price = 0;		
	}
 
	//parameterized constructor
	public Pokemon(String name, String type, double price){
		this.name = name;
		this.type = type;
		this.price = price;
	}
 
	//getters and setters
	public void setName(String name){
		this.name = name;
	}
	/*
	//alternative way to declare setter
	public void setName(String theName){
		name = theName;
	}*/
	public String getName(){
		return name;
	}
 
	public void setType(String type){
		this.type = type;
	}
	public String getType(){
		return type;
	}
 
	public void setPrice(double price){
		this.price = price;
	}
	public double getPrice(){
		return price;
	}
 
	//a custom method for the price variable
	public String getPriceFormatted(){
		NumberFormat currency = NumberFormat.getCurrencyInstance();
		String priceFormatted = currency.format(price);
		return priceFormatted;
	}
 
}

Originally Posted by Norm

One benefit would be to make the class immutable. Once it was created via a constructor, its contents would not be changeable via setter methods.

So does that mean if I have a parameterized constructor, I don't need getters and setters?

Originally Posted by jim829

That does not negate the need for one or more constructors to aid in creating an instance.

I'm sorry, but I still don't understand the need to create another constructor to overload a default constructor if you have getters and setters. And just to be clear, the reason I want to understand this is just in case it comes up in a job interview.

Originally Posted by jim829

In that case the constructor allows you to provide set the values once. You can't change them. If you used a setter to set it once, you could keep changing it. Then the class would not be immutable.

Thank you Jim, that makes sense