Method-Local Inner Classes and the final local variable

[Richard Parker]

Hello,

According to the K&B book (chapter 8), a Method-Local Inner Class cannot use variables declared within the method unless those variables are marked final.

This is because the Method-Local Inner Class object might live longer on the heap than the local variable in the method would live on the stack.
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This is all fine and dandy, but what makes a final variable so different?

Sure - the keyword final makes it impossible to reinitialize that variable once it has been initialized - but doesn't a final variable also live on the stack and therefore might still have a shorter life than the Method-Local Inner Class object?

Thanks,
Richard

[marc weber]

Because the variable is final, its value can be copied into the instance. Then when the method exits (and its variables are destroyed), the instance still has that value.

[Richard Parker]

ah - yes, thank you mark

"...value is copied" and "final var value is guaranteed to stay the same".
I was over thinking the issue.