Why object declared after one case label is available in others?

Question

Possible Duplicate:
Variable scope in a switch case

I've got a code like this:

switch(a) {
case b:
 Object o = new Object();
 return o;
case c:
 o = new Object();
 return o;
 }

and i'm interesting why it's possible to use variable declared after first case label in the second one even if first state will never be reached?

It is an exact duplicate therefore violating the rules of SO. Shame! :) — Jan Zyka, May 18 '11 at 08:28
@Jan - Without knowing the word 'scope' it may have been hard to find it. No shame. :) — Ishtar, May 18 '11 at 08:33
Asking duplicates isn't a crime, especially if the question is phrased differently. — skaffman, May 18 '11 at 09:03

score 2 · Accepted Answer · answered May 18 '11 at 08:22

2

Despite being in different cases, the variables local to the switch statement are in the same block, which means they are in the same scope.

As far as I know, new scope in Java is only created in a new block of code. A block of code (with more than one line) has to be surrounded by curly braces. The code in the cases of a switch statement is not surrounded by curly braces, so it is part of the whole statement's scope.

However, you can actually introduce a new scope to the statement by adding curly braces:

switch (cond) {
case 1:{
     Object o = new Object();
}
    break;
case 2:{
    // Object o is not defined here!
}
    break;
}

answered May 18 '11 at 08:22

Tikhon Jelvis

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Now tell me you didn't copy it over from the one flaged as duplicate :) – Jan Zyka May 18 '11 at 08:30
I actually posted before I saw the comment. That said, I should go over there and see if there is anything left to steal ;) – Tikhon Jelvis May 18 '11 at 08:35

Why object declared after one case label is available in others?

1 Answers1