Hi Juan,
I think your problem can't be solved (only) by Tomcat.
The problem is that objets stay in memory because of pointers on static
references...
To solve this :
You can embed a CleanupListener in your webapp.
This listener seem to be like this :
------------
package com.yourWebApp;
import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;
public class CleanupListener implements ServletContextListener
{
public MyCleanupListener() { super(); }
public void contextInitialized(ServletContextEvent event) { }
public void contextDestroyed(ServletContextEvent event) {
MySingleton.delInstance();
}
}
-----------
Before this, you have to
1) modify your MySingleton with :
public static void delInstance()
{
if (_instance != null) { _instance._charWidths=null; }
_instance = null;
}
2) add, in web.xml :
<listener>
<listener-class>com.yourWebApp.CleanupListener</listener-class>
</listener>
Notes :
- Perhaps your Listener will have to delete other objets like SQL drivers,
commons logger, ...
- see also :
http://opensource2.atlassian.com/confluence/spring/pages/viewpage.action?pageId=2669
Regards.
On Mon, 28 Nov 2005 08:29:13 +0000
kurrele <[EMAIL PROTECTED]> wrote:
> Hi to everyone!! This is my first email to this list, hope is the correct
> one.
>
> I've been analyzing my code with a profiler (JProbe) because I was getting
> an
> OutOfMemoryException after a few redeploys of my application.
>
> After some tests, it turned out that my static fields were not GCed after
> redeploying, getting stuck with the classloader which loaded my classes.
>
> After that, I searched the bugzilla and found
> *Bug# *(Memory Leak in Classloader/Manager deploy/undeploy)*:*
> 20758<http://issues.apache.org/bugzilla/show_bug.cgi?id=20758>
> where it says that the bug has been FIXED.
>
> I tested it in Tomcat 4.1.24 and 5.0.28 getting the same result (memory leak
> in static fields).
>
> I attach here the servlet and singleton of my simple test webapp.
>
> ---------------------------------------------------------------------------------------------------------------------------
> public class Test extends HttpServlet
> {
>
> MySingleton singleton = MySingleton.getInstance();
>
> public void init(ServletConfig config) throws ServletException
> {
> super.init(config);
>
> }
>
> public void destroy()
> {
> singleton = null;
> }
>
> protected void processRequest(HttpServletRequest request,
> HttpServletResponse response)
> throws ServletException, IOException
> {
> response.setContentType("text/html");
> PrintWriter out = response.getWriter();
> out.println("<html><head><title>JProbe TEST
> singleton</title></head><body><b>JProbe TEST
> singleton</b><BR></body></html>");
> out.close();
> }
> protected void doGet(HttpServletRequest request, HttpServletResponse
> response)
> throws ServletException, IOException
> {
> processRequest(request, response);
> }
>
> protected void doPost(HttpServletRequest request, HttpServletResponse
> response)
> throws ServletException, IOException
> {
> processRequest(request, response);
> }
> }
>
>
> -------------------------------------------------------------------------------------------------------------------------------------
> public class MySingleton
> {
>
> private static MySingleton _instance = new MySingleton();
>
> public byte[] _charWidths = new byte[1024*1024]; // 1Meg mem
> allocation!!.
>
> private MySingleton()
> {}
>
> public static MySingleton getInstance()
> {
> return _instance;
> }
>
> public void finalize()
> {
> System.out.println("!!! END-MySingleton !!!");
> _instance = null;
> }
> }
>
>
> -------------------------------------------------------------------------------------------------------------------------------------
>
> After redeploying this simple webapp a 1Meg leak can be found due to
> MySingleton not being GCed.
>
> Please I want to know If I'm leaving out something, the bug is not really
> fixed or I need to take another approach.
>
> Thanks.
>
> Juan F. S. (Spain).
>
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