retyrn type compulsory

[Arnb Sen]

Hi All,

Is it compulsory to mention the return type as "void" for methods which do not return anything ?

[Marilyn de Queiroz]

Yes. What happens when you declare a method without a return type of any kind?
[ September 03, 2005: Message edited by: Marilyn de Queiroz ]

[Arnb Sen]

Hi Marilyn,

Shows compile time error.

[Arnb Sen]

So it means that Costructor is the only method which may not have a return type. However, Constructor may have a return type.

Are the above statements correct ?

[Stuart Gray]

Try it and see. What does this class do? Does it compile?

public class Person {
 
   private String name;
   private int age;
 
   public String Person() {
   }
}

[Marilyn de Queiroz]

If a constructor has a return type, it is no longer a constructor.

[Arnb Sen]

Hi Stuart,

  
public class Person {
 
   private String name;
   private int age;
 
   public String Person() {
   }
}

The above vode results in compilation error.

However, if I change

  
   public String Person() {
   }

to

  
   public void Person() {
   }

the code compiles without any error.

So can I say that Constructors can either have no return type or can have only "void" return type ?

Also, since Marilyn mentioned

If a constructor has a return type, it is no longer a constructor.

does it mean that it is possible to have methods with same name as the class name which are not constructors ?

[Jim Yingst]

[Arnab]: So can I say that Constructors can either have no return type or can have only "void" return type ?

No, because as Marilyn said, if there's a return type (including void), it's not a constructor anymore. Unfortunately this is a case where "try it and see" doesn't really give you a clear answer. The code compiles, but it doesn't do what you think it does.

[Arnab]: does it mean that it is possible to have methods with same name as the class name which are not constructors ?

Yes, unforturnately. This is an extremely bad idea, something that you should never do when writing a program (because it's needlessly confusing to everyone), and I wish that Sun had forbidden this in the first place. Unfortunately, they didn't. So you must remember it yourself: never put a return type, including void, on a constructor - or it stops being a constructor.

[Stuart Gray]

Yeah, my bad. The example I gave doesn't compile - but for a different reason (no return statement).