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From Graham Smith <gra...@crazysquirrel.com>
Subject Re: contextInitialized being called exactly twice
Date Thu, 10 Jun 2004 19:07:16 GMT
Hi,

Thanks for the help. I took a break for an hour or so (after working on 
this nearly all day), and came to the same conclusion. I have managed to 
get it to only initialize once now but it does work as I would expect it to.

Test 1
If autoDeploy="false" and I have a context definition in the server.xml 
(<Context path="" docBase="/foo/tomcat/webapps/xfly/" debug="0"/>) then 
it calls contextInitialization twice.

Test 2
if autoDeploy="false" and I have no context in the server.xml file it 
calls contextInitialization only once but the software is then deployed 
with the wrong context

Test 3
if I rename the webapp (from webapps/xfly to webapps/ROOT), include a 
context definition of <Context path="" docBase="" debug="0"/> and leave 
autoDeploy="false" then it doesn't get deployed at all

Test 4
As test 3 but if I remove the context definition from the server.xml 
file then it deploys and calls contextInitialization only once.

Test 5
As test 4 but with autoDeploy="true" gives the same result.

Now thats all fine and good as I have a solution to my problem but it 
does seem to indicate that it's impossible to have a webapp in the hosts 
appBase directory that is deployed under a different context name from 
its directory name (well, unless you want it initialized twice). Is this 
a bug or a feature? Surely it must be fairly simple to check whether a 
particular webapp has already been deployed (possibly under a different 
context name) and not deploy it a second time if it has. I don't 
remember seeing anything in the servlet spec that forbade deploying a 
webapp twice in a since host but I don't think its what most people 
would expect.

graham

Shapira, Yoav wrote:

>Hi
>I bet it's being called once for each time the context is deployed, and
>the context is deployed twice because you have autoDeploy on AND an
>explicit context declaration in your server.xml/conf directory/WAR.
>Turn autoDeploy off and see what happens.
>
>(This would explain the static counter being 1: the counter is static
>once per classloader repository, you have two of the same context at
>different paths with different classloader repositories).
>
>Yoav Shapira
>Millennium Research Informatics
>
>
>  
>
>>-----Original Message-----
>>From: Graham Smith [mailto:graham@crazysquirrel.com]
>>Sent: Thursday, June 10, 2004 12:32 PM
>>To: tomcat-user@jakarta.apache.org
>>Subject: contextInitialized being called exactly twice
>>
>>Hi,
>>
>>I am absolutely stumped by this problem. For some reason that I can't
>>fathom the contextInitialized method on a ServletContextListener I have
>>in one of my web applications is being called twice. Normally this
>>    
>>
>isn't
>  
>
>>a problem since it only causes the load process to take longer but I
>>have recently added a new section that starts a daemon thread and it
>>this double call is causing two threads to be created. What is even
>>    
>>
>more
>  
>
>>bizarre is that I have tried using a static int to count the number of
>>times the method is called but it always returns one. I suspected that
>>it therefore must be created by a different class loader but a call to
>>getClass().getClassLoader and a dump (see below) of information would
>>seem to indicate that it is in fact the same class loader loading the
>>class. I am using tomcat 5.0.25 on Linux with Java 1.4.2_04. I have
>>    
>>
>also
>  
>
>>performed a thread dump in order to check that it is _really_ being run
>>twice and sure enough there are two copies of my thread running (again
>>see extract below).
>>
>>Any help would be greatly appreciated.
>>
>>Graham
>>
>>ClassLoader dump:
>>----------------------------------------------------
>>First time it is loaded
>>----------------------------------------------------
>>ClassLoader: WebappClassLoader
>>  delegate: false
>>  repositories:
>>----------> Parent Classloader:
>>StandardClassLoader
>>  delegate: true
>>  repositories:
>>    file:/home/gms/dump/tomcat/shared/classes/
>>----------> Parent Classloader:
>>StandardClassLoader
>>  delegate: true
>>  repositories:
>>    file:/home/gms/dump/tomcat/common/classes/
>>    file:/home/gms/dump/tomcat/common/endorsed/xercesImpl.jar
>>    file:/home/gms/dump/tomcat/common/endorsed/xmlParserAPIs.jar
>>    file:/home/gms/dump/tomcat/common/lib/ant.jar
>>    file:/home/gms/dump/tomcat/common/lib/commons-collections.jar
>>    file:/home/gms/dump/tomcat/common/lib/commons-dbcp-1.1.jar
>>    file:/home/gms/dump/tomcat/common/lib/commons-el.jar
>>    file:/home/gms/dump/tomcat/common/lib/commons-pool-1.1.jar
>>    file:/home/gms/dump/tomcat/common/lib/jasper-compiler.jar
>>    file:/home/gms/dump/tomcat/common/lib/jasper-runtime.jar
>>    file:/home/gms/dump/tomcat/common/lib/jsp-api.jar
>>    file:/home/gms/dump/tomcat/common/lib/naming-common.jar
>>    file:/home/gms/dump/tomcat/common/lib/naming-factory.jar
>>    file:/home/gms/dump/tomcat/common/lib/naming-java.jar
>>    file:/home/gms/dump/tomcat/common/lib/naming-resources.jar
>>    file:/home/gms/dump/tomcat/common/lib/servlet-api.jar
>>----------> Parent Classloader:
>>sun.misc.Launcher$AppClassLoader@136228
>>
>>
>>----------------------------------------------------
>>Second time it is loaded
>>----------------------------------------------------
>>
>>ClassLoader: WebappClassLoader
>>  delegate: false
>>  repositories:
>>----------> Parent Classloader:
>>StandardClassLoader
>>  delegate: true
>>  repositories:
>>    file:/home/gms/dump/tomcat/shared/classes/
>>----------> Parent Classloader:
>>StandardClassLoader
>>  delegate: true
>>  repositories:
>>    file:/home/gms/dump/tomcat/common/classes/
>>    file:/home/gms/dump/tomcat/common/endorsed/xercesImpl.jar
>>    file:/home/gms/dump/tomcat/common/endorsed/xmlParserAPIs.jar
>>    file:/home/gms/dump/tomcat/common/lib/ant.jar
>>    file:/home/gms/dump/tomcat/common/lib/commons-collections.jar
>>    file:/home/gms/dump/tomcat/common/lib/commons-dbcp-1.1.jar
>>    file:/home/gms/dump/tomcat/common/lib/commons-el.jar
>>    file:/home/gms/dump/tomcat/common/lib/commons-pool-1.1.jar
>>    file:/home/gms/dump/tomcat/common/lib/jasper-compiler.jar
>>    file:/home/gms/dump/tomcat/common/lib/jasper-runtime.jar
>>    file:/home/gms/dump/tomcat/common/lib/jsp-api.jar
>>    file:/home/gms/dump/tomcat/common/lib/naming-common.jar
>>    file:/home/gms/dump/tomcat/common/lib/naming-factory.jar
>>    file:/home/gms/dump/tomcat/common/lib/naming-java.jar
>>    file:/home/gms/dump/tomcat/common/lib/naming-resources.jar
>>    file:/home/gms/dump/tomcat/common/lib/servlet-api.jar
>>----------> Parent Classloader:
>>sun.misc.Launcher$AppClassLoader@136228
>>
>>
>>
>>----------------------------------------------------
>>Extract of thread dump
>>----------------------------------------------------
>>
>>......
>>
>>
>>"ContainerBackgroundProcessor[StandardEngine[Catalina]]" daemon prio=1
>>tid=0x0848eb98 nid=0x7d54 waiting on condition [4d90d000..4d90d854]
>>        at java.lang.Thread.sleep(Native Method)
>>        at
>>org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.run
>>    
>>
>(Con
>  
>
>>tainerBase.java:1597)
>>        at java.lang.Thread.run(Thread.java:534)
>>
>>"category statistics generator" daemon prio=1 tid=0x082e6960 nid=0x7d54
>>waiting on condition [4e1de000..4e1de854]
>>        at java.lang.Thread.sleep(Native Method)
>>        at
>>com.crazysquirrel.xfly.category.CategoryStats.run(CategoryStats.java:73
>>    
>>
>)
>  
>
>>        at java.lang.Thread.run(Thread.java:534)
>>
>>"directory cleaner" daemon prio=1 tid=0x0852dd30 nid=0x7d54 waiting on
>>condition [4e15d000..4e15d854]
>>        at java.lang.Thread.sleep(Native Method)
>>        at
>>com.crazysquirrel.xfly.web.DirectoryCleaner.run(DirectoryCleaner.java:8
>>    
>>
>0)
>  
>
>>        at java.lang.Thread.run(Thread.java:534)
>>
>>"category statistics generator" daemon prio=1 tid=0x085072f8 nid=0x7d54
>>waiting on condition [4e0dc000..4e0dc854]
>>        at java.lang.Thread.sleep(Native Method)
>>        at
>>com.crazysquirrel.xfly.category.CategoryStats.run(CategoryStats.java:73
>>    
>>
>)
>  
>
>>        at java.lang.Thread.run(Thread.java:534)
>>
>>"directory cleaner" daemon prio=1 tid=0x084e7ea8 nid=0x7d54 waiting on
>>condition [4e05b000..4e05b854]
>>        at java.lang.Thread.sleep(Native Method)
>>        at
>>com.crazysquirrel.xfly.web.DirectoryCleaner.run(DirectoryCleaner.java:8
>>    
>>
>0)
>  
>
>>        at java.lang.Thread.run(Thread.java:534)
>>
>>"Signal Dispatcher" daemon prio=1 tid=0x08096a50 nid=0x7d54 waiting on
>>condition [0..0]
>>
>>........
>>
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>>    
>>
>
>
>
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