Re: final variables as parameters due to action listeners

Thomas Hawtin <>
Mon, 01 May 2006 07:37:50 +0100
<4455b917$0$9258$> wrote:

I have the following code which complains with 'Cannot refer to a
non-final variable controlPanel inside an inner class defined in a
different method':


If however I change the parameter to be final

private void addPanelListeners(final PanelAddRemove controlPanel) {

it no longer complains. I must confess I used to create a private
variable in the class as a work around which worked but was ugly.

Erm yes, bad idea...

are there any detrimental side effects to making the object final - I
assume it means dont point controlPanel to another value - but
otherwise it is fine?

It's technically the reference which is final, not the object itself.
It's fine. Some people make all local variables final unless they need
to be mutable. I think it would have been better to make final the default.

Tom Hawtin
Unemployed English Java programmer

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