在tomcat上运行Web应用程序

Question

I am trying to profile tomcat server. My profiler outputs list of methods which were executed by the tomcat server. I use Ubuntu 12.04. What I do is as follow:

1) start the tomcat server (./startup.sh)

2) open the browser and execute the web application develooped in java (and contains jsp pages)for eg (http://localhost:8080/bodgeit.) I have put bodgeit web application in webapps directory of tomcat 7.0.28 (I run bodgeit web application on tomcat)

3) I perform some actions in this webapplication like login, adding things to basket, changing password, logout etc.

4) then I stop the server by ./shutdown.sh. When I run shudown script, my profiler outputs the file which contains list of methods executed while running the tomcat.

Now my question is: I collect profiles two or more times by performing the above steps. I perform exactly same action in web application( in same sequence) in step 3. But sequence of methods I get in both the outputs are different. Why is it so ? My profiler is capable of saving method sequence also.

Do methods executed by apache web serever differ everytime ? aren't they fixed ? like certain methods are executed when you start a server, when you make a request or when you shutdown a server ? I am new to tomcat, servlet and jsp too. I have basic idea about how it works. For eg following sequence does not exist in 1st file and exist in 2nd file. Like this, there are many more differences.

<callingContextTree><method declaringClass="Lorg/apache/catalina/startup/HostConfig$DeployWar;" name="run" params="" return="V"><callsite instruction="7"><method declaringClass="Lorg/apache/catalina/startup/HostConfig;" name="deployWAR" params="Lorg/apache/catalina/util/ContextName; Ljava/io/File;" return="V"><callsite instruction="555"><method declaringClass="Lorg/apache/catalina/core/StandardHost;" name="addChild" params="Lorg/apache/catalina/Container;" return="V"><callsite instruction="20"><method declaringClass="Lorg/apache/catalina/core/ContainerBase;" name="addChild" params="Lorg/apache/catalina/Container;" return="V"><callsite instruction="15"><method declaringClass="Lorg/apache/catalina/core/ContainerBase;" name="addChildInternal" params="Lorg/apache/catalina/Container;" return="V"><callsite instruction="75"><method declaringClass="Lorg/apache/catalina/util/LifecycleBase;" name="start" params="" return="V"><callsite instruction="88"><method declaringClass="Lorg/apache/catalina/core/StandardContext;" name="startInternal" params="" return="V"><callsite instruction="517"><method declaringClass="Lorg/apache/catalina/util/LifecycleBase;" name="start" params="" return="V"><callsite instruction="88"><method declaringClass="Lorg/apache/catalina/session/StandardManager;" name="startInternal" params="" return="V"><callsite instruction="4"><method declaringClass="Lorg/apache/catalina/session/StandardManager;" name="load" params="" return="V"><callsite instruction="43"><method declaringClass="Lorg/apache/catalina/session/StandardManager;" name="doLoad" params="" return="V"><callsite instruction="61"><method declaringClass="Lorg/apache/catalina/core/ContainerBase;" name="getLoader" params="" return="Lorg/apache/catalina/Loader;"/></callsite></method></callsite></method></callsite></method></callsite></method></callsite></method></callsite></method></callsite></method></callsite></method></callsite></method></callsite></method></callsite></method></callingContextTree>

Can somebody please help me to find what's happening ? In short say, if I start the server, access home page of tomcat and stop the server. I do exactly this again. Does tomcat execute same methods in same sequence both time ? As far as I have noticed, it does not. why ?

Thank you.

Answer 1

It looks like Tomcat is auto-reloading web applications while you are using it. You might want to check the timestamps on your files relative to the system clock on your machine. If you have files modified in the future, you can trigger this kind of behavior. Check your logs/catalina.out to see if there is any auto-deployment activity going on.