Re: Using ReentrantLock

From:
Lew <noone@lewscanon.com>
Newsgroups:
comp.lang.java.programmer
Date:
Sat, 22 Aug 2009 20:10:11 -0400
Message-ID:
<h6q1da$6sp$1@news.albasani.net>
Arne Vajh??j wrote:

Lew wrote:

Arne Vajh??j wrote:

I was actually talking about the similar but slightly different
situation where the object are made available after assignment.

Object o = new Object();
something(o);
// now o could be shared among threads if the something made it so


Provided 'o' is 'final'.


I can not see why final or non-final should make a difference
here.


First there is the JLS that says (17.4.1):

Local variables (??14.4), formal method parameters (??8.4.1) or
exception handler parameters are never shared between threads
and are unaffected by the memory model.


The only way I know of to get a thread to share a local variable value is as
an inner class that refers to a variable in the invoking context, which
requires that the outer variable be 'final'.

JLS 8.1.3:

Any local variable, formal method parameter or
exception handler parameter used but not declared in an inner class
must be declared final.


--
Lew

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