[WICKET-438] File handles are leaked when loading images from a jar file, Tomcat crashes

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.2.5
• Fix Version/s: 1.2.6, 1.3.0-beta1
• Component/s: wicket
• Environment: java version "1.5.0_07", Mac OS X 10.4, Tomcat 5.5.20; and also ; java version "1.5.0_07", Linux 2.6.8, Tomcat 5.5.17; Firefox 2.0.3 with Web developer Toolbar
• Assignee: Johan Compagner
• Reporter: Stefan Wille
• Created: 30/Mar/07 17:19
• Updated: 21/Apr/07 20:44
• Resolved: 21/Apr/07 20:44

Description

Wicket leaks file handles when it accesses image files that are part of a jar file, e.g. wicket-1.2.5.jar.

To reproduce this bug, please switch off the browser cache.

My Wicket application uses TreeTable. When I access the page with the TreeTable on my Mac server, I see the number of open file handles jump. If I do that repeatedly, I can leak about 50 file handles.

I observe the number of open file handles via this shell command: while true; do sleep 1; lsof | grep wicket | wc -l; done

If I do the same test on a Linux server, the number of open files jumps so quickly that I reach 1015 open files after about 4 requests. At this point, Tomcat runs out of file handles, writes a log entry in catalina.out and dies. Probably Tomcat shouldn't crash, but the problem is that Wicket leaks file handles.

I can also see leaked file handles when I repeatedly access an image from a jar file via http://localhost:8070/wicket-examples/ajax/resources/wicket.extensions.markup.html.tree.DefaultAbstractTree/res/tree-images.png

The problem can also be reproduced via wicket-examples 1.2.5 and its TreeTable example page by exanding and collapsing the tree table repeatedly.

If I unpack both wicket-1.2.5.jar and wicket-extensions-1.2.5.jar in WEB-INF/classes and delete the jars afterwards, the number of used file handles remains constant at 5! So access to images in WEB-INF/classes works fine.

"lsof | grep wicket" gives me:

firefox-b 1372 stefan 19r REG 14,2 486664 1733273 /Users/stefan/Software/apache-tomcat-5.5.20/webapps/middletier/WEB-INF/lib/wicket-extensions-1.2.5.jar
bash 1880 stefan cwd DIR 14,2 578 1058285 /Users/stefan/Software/wicket-1.2.5
bash 4339 stefan cwd DIR 14,2 578 1058285 /Users/stefan/Software/wicket-1.2.5
java 9529 stefan txt REG 14,2 1249210 1750285 /Users/stefan/Software/apache-tomcat-5.5.20/webapps/middletier/WEB-INF/lib/wicket-1.2.zoomos-SNAPSHOT.jar
java 9529 stefan txt REG 14,2 486664 1750274 /Users/stefan/Software/apache-tomcat-5.5.20/webapps/middletier/WEB-INF/lib/wicket-extensions-1.2.5.jar
java 9529 stefan txt REG 14,2 11063 1750305 /Users/stefan/Software/apache-tomcat-5.5.20/webapps/middletier/WEB-INF/lib/wicket-spring-annot-1.2.5.jar
java 9529 stefan txt REG 14,2 24890 1750306 /Users/stefan/Software/apache-tomcat-5.5.20/webapps/middletier/WEB-INF/lib/wicket-spring-1.2.5.jar
java 9529 stefan 29r REG 14,2 486664 1750274 /Users/stefan/Software/apache-tomcat-5.5.20/webapps/middletier/WEB-INF/lib/wicket-extensions-1.2.5.jar
java 9529 stefan 30r REG 14,2 486664 1750274 /Users/stefan/Software/apache-tomcat-5.5.20/webapps/middletier/WEB-INF/lib/wicket-extensions-1.2.5.jar
java 9529 stefan 31r REG 14,2 486664 1750274 /Users/stefan/Software/apache-tomcat-5.5.20/webapps/middletier/WEB-INF/lib/wicket-extensions-1.2.5.jar
java 9529 stefan 32r REG 14,2 486664 1750274 /Users/stefan/Software/apache-tomcat-5.5.20/webapps/middletier/WEB-INF/lib/wicket-extensions-1.2.5.jar
java 9529 stefan 33r REG 14,2 486664 1750274 /Users/stefan/Software/apache-tomcat-5.5.20/webapps/middletier/WEB-INF/lib/wicket-extensions-1.2.5.jar
java 9529 stefan 34r REG 14,2 486664 1750274 /Users/stefan/Software/apache-tomcat-5.5.20/webapps/middletier/WEB-INF/lib/wicket-extensions-1.2.5.jar
java 9529 stefan 35r REG 14,2 486664 1750274 /Users/stefan/Software/apache-tomcat-5.5.20/webapps/middletier/WEB-INF/lib/wicket-extensions-1.2.5.jar
java 9529 stefan 36r REG 14,2 486664 1750274 /Users/stefan/Software/apache-tomcat-5.5.20/webapps/middletier/WEB-INF/lib/wicket-extensions-1.2.5.jar
java 9529 stefan 37r REG 14,2 486664 1750274 /Users/stefan/Software/apache-tomcat-5.5.20/webapps/middletier/WEB-INF/lib/wicket-extensions-1.2.5.jar
java 9529 stefan 38r REG 14,2 486664 1750274 /Users/stefan/Software/apache-tomcat-5.5.20/webapps/middletier/WEB-INF/lib/wicket-extensions-1.2.5.jar
java 9529 stefan 39r REG 14,2 486664 1750274 /Users/stefan/Software/apache-tomcat-5.5.20/webapps/middletier/WEB-INF/lib/wicket-extensions-1.2.5.jar
java 9529 stefan 40r REG 14,2 486664 1750274 /Users/stefan/Software/apache-tomcat-5.5.20/webapps/middletier/WEB-INF/lib/wicket-extensions-1.2.5.jar
java 9529 stefan 41r REG 14,2 486664 1750274 /Users/stefan/Software/apache-tomcat-5.5.20/webapps/middletier/WEB-INF/lib/wicket-extensions-1.2.5.jar
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