Is it a garbage collector issue?

Hello,
lets say that I have an object of List called navList in my JSP, I assign 10 values to navList, the 10 values are timestamp in milliseconds.
now when I refresh the page I assume that new 10 values should be in navList, but for my supprise I find out that now I have 20 values; 10 values that correspond to the old timestamp and another 10 for the new timestamp.
and when I refersh the page for the third time I get 30 values, with the 20 old values and a new 10 value. the number keep increasing by 10 values every time I refresh or reopen the page.
so my assumption is that the garabage collector is not destroying the navList object, is that assumption correct?
Thanks

I have followed the link that was provided by jag_prg, and applied what was disscussed there. it did solve my problem.
I have added this directive to my jsp:
<%@ page isThreadSafe="true" %>
and modifieded <%! %>:
<%!
List navList = null
%>
and modifieded <% %>:
<%
navList = new ArrayList();
%>
this three changs solved the my issue,
Thank you jag_prg and bsampieri

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    I don't know for sure about the syntax of Objective-C 2.0. That stuff is all new. What error message are you getting that indicated that (copy, readwrite) is required? Could you provide a link to the actual example source? I did a quick check and assign and readwrite are the defaults. It is possible that readwrite by itself makes no sense. But I'm just guessing.

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