overloading constructors

Question

I have a 3 questions on overloaded constructors:

1.On the line marked line 1, I am calling an overloaded constructor but the compiler doesn't resolve the call,
is there something else I need to do?

On the line marked with a 2, The compiler complains that the "this()" needs to be the first statement in the method, when it is. What's with that?
If I am writing an overloaded constructor, and I haven't overridden the default constructor do I need an explicit "this();" in the overloaded constructor, if i want to execute the behavior of the default constructor, or is it included in all constructors for "free"?

.

class JavaSnippet {


public static void main(String[] args) {

          String MenuItemName="Coffee";
          double MenuItemPrice=1.0;
          Item MenuItem;
     //1-> MenuItem=new Item(MenuItemName,MenuItemPrice);// Get "cannot find symbol"
    }
}         

 class Item {
    String name;
     double price;

      public void  Item(String InName, double InPrice)   {
// 2-> this();// get "call to this must be first statement in constructor"


     name=InName;
     price=InPrice;
     }

}

maybe it is too late already but i can not see an error there. hm. never mind... nevertheless, please dont use capital letters at the beginning of reference names, it is a matter of style of course. but you will soon see it is easier to distinguish between class names and other stuff. a common way of naming style is something like: class names - capital letter at beginning, reference - small letters, constants - capital letters ... — mad
– mad, Commented Dec 12, 2010 at 22:41
ahhh found one - dont write "void" in front of item constructor, this should do both errors — mad
– mad, Commented Dec 12, 2010 at 22:44

Bozho · Accepted Answer · 2010-12-12 22:45:38Z

3

Currently you are not defining a constructor. It should not have a return type (yours has void). So:

public Item(String InName, double InPrice) { .. }

Then, calling this() will not work again. When you define a constructor with arguments, the default (no-arg) constructor is "lost". So you can't call it. And in your case - you don't need it.

(Also note that variable names in Java should start with lower-case (by convention))

edited Dec 12, 2010 at 22:45

answered Dec 12, 2010 at 22:37

Bozho

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Matten · Accepted Answer · 2010-12-12 22:46:38Z

2

Your Constructor has a method signature. The constructor of item should be

public Item(String InName, double InPrice) { ... }

and not

public void Item(...)

And your second question: If you want to call the other (not overriden, but explicitely defined parameterless) constructor, you need an explicit call to this(). If you want to call a constructor from a super-class, the call is super().

edited Dec 12, 2010 at 22:46

answered Dec 12, 2010 at 22:37

Matten

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