final variable question from kb

[Dinesh Tahiliani]

Rancher,

Need your help in this

class Knowing
{
static final long toth = 343L;
static long doit(long tooth)
{
System.out.println(++tooth);
return ++tooth;
}

public static void main(String [] a)
{
System.out.println(tooth);
final long tooth=340L;
newkKnowing().doit(tooth);
System.out.println(tooth);
}

}
o/p 343,341,340

Can anyone expalin me this
How can final variable been modified

[marc weber]

Dinesh, after 349 posts, it's time you learn the beauty of Code Tags. Please use these whenever posting code.

There are 3 different variables called "tooth" in this example:

A final variable in the class Knowing.

A non-final local variable in the method doit.

A final local variable in the method main.

Keep in mind that whenever you pass a primitive to a method, you are passing a copy of that value, which is assigned to a local variable.

[Dinesh Tahiliani]

which value is here than pass ??

[Christophe Verré]

a copy of the final variable, not the final variable itself.

[Dinesh Tahiliani]

In this case will be what 340L or 343L ???

[Christophe Verré]

First,

System.out.println(tooth); // Printing the static variable
final long tooth=340L; // declaring a local variable
newkKnowing().doit(tooth); // passing a copy of the variable
System.out.println(tooth); // Printing the local variable (which has not been modified)

And then

static long doit(long tooth) // this is a local variable
{
System.out.println(++tooth); // increment the local variable and output
return ++tooth; // output the local variable and return
}

With all the comment, can you figure out what is going to be output ?

[Dinesh Tahiliani]

Thanks for excellent reply...