Re: servlet reference and thread safe

From:
"Daniel Pitts" <googlegroupie@coloraura.com>
Newsgroups:
comp.lang.java.programmer
Date:
10 Nov 2006 17:33:53 -0800
Message-ID:
<1163208833.160789.254940@f16g2000cwb.googlegroups.com>
gk wrote:

hiwa wrote:

gk wrote:

"...the instance , static variables used in a servlet reference
object are not thread safe..."

 why instance variables are not thread safe ?

 say i have

 class MyServlet extends HttpServlet
 {
Sting x;
String y;

//doGet()

//doPost()

}

How , this x,y cant be thraed safe ?

seperate instance will have there own copy and hence they are not
going to be mixed up in multithreading enviornment.
so, these variables are thread safe .

could you please explain ...why that statement is correct ?

this x,y cant be thraed safe ?

No. They can't be, unless their accesses are synchronized.
Only local variables in methods are thread safe because local variables
are allocated on the stack per each call.


if i make synchronized setter/getter methods to access those instance
variables , will that be thread safe now ?


Or, if the referenced objects are threadsafe (String objects are), then
you can use AtomicReference.

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