Sybex CSG 17 - Varargs in method signature on page 167 (Chapter 4)

[Rik Vo]

On the bottom of page 167 (in the section Formatting Values of Chapter 4), the following method signatures are stated:

public static String format(String format, Object args...)
public static String format(Locale loc, String format, Object args...)
public String formatted(Object args...)

However, shouldn't "..." be after Object instead of args?

[Piet Souris]

hi Rik,

welcome to the Ranch!

You are right, the ellipsis should be after Object.

[Campbell Ritchie]

Yes, as you and Piet both said, it is better style to have the ... as part of the type rather than the parameter name. But the compiler will accept both. If you look in the Formatter documentation, you will find the better format used. Strictly speaking, the method signature should not include parameter names.

[Mike Simmons]

Campbell Ritchie wrote:But the compiler will accept both.

That's not true. You may be thinking of array type declarations.  For historical (C language) reasons, Java has always accepted either

Object[] array = ...

or

Object array[] = ...

However, that does not extend to vararg declarations. In Java, the ... needs to be after the type, not the variable name.  So always

public void method(Object... args)

never

public void method(Object args...) // does not compile

[Soner Akar]

Campbell Ritchie wrote:Yes, as you and Piet both said, it is better style to have the ... as part of the type rather than the parameter name. But the compiler will accept both. If you look in the Formatter documentation, you will find the better format used. Strictly speaking, the method signature should not include parameter names.

As said in prior comment,  

But the compiler will accept both.

doesn't seem right.

[Jeanne Boyarsky]

Welcome to CodeRanch!

You are correct. I've added this to the errata and credited you.