Java Memory leak 1

crmayer · Nov 12, 2008

I know that this is not supposed to happen in Java, but I have a memory leak with a servlet that I was wondering if somebody could tell me where my problem might be?

I have done everything I can think of and it still exsists.

The only thing I can think is that the page that is creates is set to refresh every 30 seconds, but I can not believe that I am the only one doing that....

Below is my code:
package com.tms.server.loadmaster.www;

import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;
import com.tms.common.remote.lib.data.Query;
import com.tms.common.lib.StringList;

import com.tms.common.remote.lib.data.DataFactory;
import com.tms.common.loadmaster.

http://www.*;

import com.tms.common.lib.data.TableDescriptor;
import com.tms.common.lib.Application;

/**
* Title: FccBrokerLoadServlet
* Description: Web site listing of avaible broker loads
* Copyright: Copyright (c) 2002
* Company: Fremont Contract Carriers
* @author not attributable
* @version 1.0
*/

public class FccBrokerLoadServlet extends HttpServlet
{
private static final String modRcsId = "$Id: FccBrokerLoadServlet.java,v 1.1 2008/09/26 19:02:20 mayer Exp $";

private WebUtil webutil;

public void doGet(HttpServletRequest request, HttpServletResponse response)
throws
ServletException, IOException
{
HttpSession session = request.getSession(true);
String username = null;
response.setContentType("text/html");

//BEGIN - chrism - 07112008
//String tmpDir = Application.getBaseDir() + File.separatorChar + "www"
// + File.separatorChar + "html" + File.separatorChar
// + "scripts" + File.separatorChar + "AutoRefreshPage.js";
//File auto_refresh = new File(tmpDir);
PrintWriter out = response.getWriter();

if (session.isNew()) {
out.println("You have an invalid session or your session has expired");
out.println("attempted security breach or session expried.");
out.close(); //still searching for leak...
session = null; //still search for leak...
return;
} else {
username = (String) session.getAttribute("user.account");
out.close(); //not sure about the memory leak
session = null; //again?????
}
webutil = new WebUtil(username);
response.addHeader("Refresh", "30"); //testing java's auto-refresh
out.println(webutil.getHeader());
//END - chrism - 07112008
out.println("<div align=\"center\">");
//chrism 07112008
out.println("Fremont Transportation Services Available Loads");
out.println("Thanks for your interest in FCC Transportation Services.");
out.println("This page is updated every 30 seconds. For detailed load information, including rates please contact us at:");
out.println("1-800-228-9842  Ext. 281");
//BEGIN - chrism - 09302008
//OLD AUTO REFRESH java script that was being loaded.
/*try{
out.println(webutil.getHTMLString(auto_refresh));
} catch (Exception ex) {
ex.printStackTrace();
}*/
//OLD AUTO REFRESH java script that was being loaded.
//END - chrism - 09302008
out.println("<TABLE width=\"900\" cellspacing=\"1\" border=\"1\">");
out.println("<TR><TD width=\"75\" bgcolor=\"#FF0000\">ORDER #</TD>");
out.println("<TD width=\"220\" bgcolor=\"#FF0000\">ORIGIN</TD>");
out.println("<TD width=\"155\" bgcolor=\"#FF0000\">PICKUP APPT.</TD>");
out.println("<TD width=\"220\" bgcolor=\"#FF0000\">DESTINATION</TD>");
out.println("<TD width=\"155\" bgcolor=\"#FF0000\">DELIVERY APPT.</TD>");
out.println("<TD width=\"75\" bgcolor=\"#FF0000\">MILES</TD>");
out.println("<TD width=\"50\" bgcolor=\"#FF0000\">TYPE</TD>");
out.println("<TD width=\"50\" bgcolor=\"#FF0000\">LBS.</TD></TR>");

try {
getBrokerLoads(out);
} catch (Exception ex) {
ex.printStackTrace();
}
out.println("</TABLE>");
out.println("</div>");

out.println("<div align=\"center\"><a href=\"/servlet/com.tms.server.loadmaster.

http://www.MenuServlet\">Back

To Menu</a> </div>");
out.println("</BODY>");
out.println("</HTML>");

out.close(); //testing memory leak problems....
session = null; //testing memory leak problems...
// response.flushBuffer();
}

public void getBrokerLoads(PrintWriter out)
{
try{
Query tmpQuery = DataFactory.createQuery();
tmpQuery.setTableName("movement");
tmpQuery.addField("origin.order_id order_id");
tmpQuery.addField("origin.city_name origin_city");
tmpQuery.addField("origin.state origin_state");
tmpQuery.addField("origin.sched_arrive_early pickup");
tmpQuery.addField("dest.city_name dest_city");
tmpQuery.addField("dest.state dest_state");
tmpQuery.addField("dest.sched_arrive_early delivery");
tmpQuery.addField("movement.move_distance");
tmpQuery.addField("orders.weight weight"); //chrism 07112008
tmpQuery.addField("orders.equipment_type_id trailer"); //chrism07142008
TableDescriptor originGroupTable = new TableDescriptor("stop origin",
"movement.origin_stop_id = origin.id", false);
tmpQuery.addJoin(originGroupTable);
TableDescriptor destGroupTable = new TableDescriptor("stop dest",
"movement.dest_stop_id = dest.id", false);
tmpQuery.addJoin(destGroupTable);
TableDescriptor ordersGroupTable = new TableDescriptor("orders",
"dest.order_id = orders.id", false);
tmpQuery.addJoin(ordersGroupTable);
tmpQuery.addWhere("movement.brokerage", "Y");
tmpQuery.addWhere("movement.status", "A");
tmpQuery.addOrderBy("origin.sched_arrive_early"); //chrism 08202008
tmpQuery.open();

while (tmpQuery.inBounds())
{
out.println("<TR><TD width=\"75\">" + tmpQuery.getString("order_id") + "</TD>");
out.println("<TD width=\"220\">" + tmpQuery.getString("origin_city") + ", " + tmpQuery.getString("origin_state") + "</TD>");
out.println("<TD width=\"155\">" + tmpQuery.getDate("pickup").toString() + "</TD>");
out.println("<TD width=\"220\">" + tmpQuery.getString("dest_city") + ", " + tmpQuery.getString("dest_state") + "</TD>");
out.println("<TD width=\"155\">" + tmpQuery.getDate("delivery").toString() + "</TD>");
out.println("<TD width=\"75\">" + tmpQuery.getString("movement.move_distance") + "</TD>");
out.println("<TD width=\"50\">" + tmpQuery.getString("trailer") + "</TD>");
if(!tmpQuery.isNull("weight"))
out.println("<TD width=\"50\">" + tmpQuery.getString("weight") + "</TD></TR>");
else
out.println("<TD width=\"50\">0.0</TD></TR>");
tmpQuery.next();
}
tmpQuery.close();
}catch (Throwable ex){
ex.printStackTrace();
}
}

}

Diancecht · Nov 12, 2008

I think you should specify what do you mean with "memory leak". OutOfMemoryException?

Maybe your query brings a load of data, maybe you should set a expires time for your session, maybe your app server has not enough memory ...

Cheers,
Dian

crmayer · Nov 12, 2008

Sorry for the breif explaination...
The query only brings back a maximum of 15 records at any given time.
I do have expires times on the sessions, but I think it is set at 60 minutes.
I have not seen an OutOfMemoryException, but I honestly believe that is because I can not allow that to happen.

We run this with JBoss and as the memory continues to baloon on that, the performace of the entire system goes down to a point where people can not work. That is when I am forced to reboot the server...

Again, I am sorry for the bad explaination of the problem. I know that memory leaks are sometimes very hard to find, so I guess I am not asking if there is on in that class, but does anybody see anything that "might" or "could" cause me problems witht that servlet.

I feel like I am closing everything, or setting it to null after it is not being used.....

Thanks

Diancecht · Nov 13, 2008

Maybe it's time for a profiling tool like this

Cheers,
Dian

crmayer · Nov 13, 2008

Thanks,
You are probably right, it is time that we look into something like this.

I will give this a shot...

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Java Memory leak 1

crmayer

Programmer

Diancecht

Programmer

crmayer

Programmer

Diancecht

Programmer

crmayer

Programmer

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