Urgent-switch case

[Vrunda Joshi]

hi,
i have just solved a mock exam.i am doubtful for a question.the question was
True/False
"In a swith statement,the argument to the case label(case:argument) can be any variable which can fit within an int."

As per my knowledge,the allowable value for the case label can be of integral type ie: char,short,byte & int.
so the ans for this question could be true.
but the ans given is false and the explanation given is
" The case argument must be either an int literal or an int compatible variable which is constant (ie: static final) "
Can anybody help me with the clarification of these question/ans.This is a bit Urgent
Thanks in advance.
-Vrunda Divekar

[Valentin Crettaz]

From JLS 14.10 The switch Statement

The type of the Expression must be char, byte, short, or int, or a compile-time error occurs.
The problem here is that a long primitive like 12L fits perfectly within an int but a long is not allowable in a case expression.
If you try to compile the following code

public class Test {
public static void main(String args[]){
int i=8;
switch(i){
case 12L: break;
default: break;
}
}
}

it gives you the following error:

Test.java:5: possible loss of precision
found   : long
required: int
                        case 12L: break;
                             ^
1 error

[ June 12, 2002: Message edited by: Valentin Crettaz ]

[Anna Dow]

You may use variables for case label, but only if they are constants (that is, final). For example, the code:

 int i=0;
    final int j=0;
    switch (i){
        case j: ;//1
        default :;
    } 

compiles fine. If you do not decalare j as final, compiler gives error 'constant expression required' for line 1