Unable to delete WEB-INF\\lib\*.jar using ant

Question

Using ant to build struts.
This is part of the build.xml for struts-example.war
<property name="deploy.dir" value="${tomcat.home}/webapps"/>
<target name="cleanWebApp">
<delete file="${deploy.dir}/${war.file.name}" />
<delete dir="${deploy.dir}/${war.file}" includeEmptyDirs="true" />
</target>
But when I try to build and reload it to tomcat, it gives me errors:
cleanWebApp:
[delete] Deleting: D:\jakarta-tomcat-5.5.7\webapps\struts-example.war
[delete] Deleting directory D:\jakarta-tomcat-5.5.7\webapps\struts-example
BUILD FAILED
D:Java\code\struts\strutsexamples\build.xml:46: Unable to delete file D:\jakarta-tomcat-5.5.7\webapps\struts-example\WEB-INF\lib\commons-digester.jar
Also lib\struts.jar(maybe more) can't be deleted.
Now I have to stop tomcat, delete it manually, and reinstall the war.
How can I fix this problem?

Answer 1

All the advice above seems to make sense, but .....
- Tomcat shutdown,
- with all java processes shutdown,
- after a full reboot,
- with antiJARLocking="true" set in every context.xml I can find:
[delete] Deleting directory C:\Program Files\Apache Software
Foundation\Tomcat 5.5\webapps\myApp
BUILD FAILED
C:\myApp\build.xml:118: Unable to delete file C:\Program Files\Apache
Software Foundation\Tomcat 5.5\webapps\myApp\WEB-INF\lib\antlr.jar
But I CAN delete the jars using the normal Windows Explorer or from the DOS Command Prompt.
And per the advice found here:
http://saloon.javaranch.com/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic&f=67&t=000574
I've downloaded the Process Explorer from www.sysinternals.com and no windows processes appear to have a handle on there directory.
I think the solution is indeed to exclude jar files from <delete> target.
Regards,
Stewart