[Tomcat] How to pass application specific parameters to the JVM?

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Sven Jacobs - 20 Feb 2006 07:29 GMT

Dear newsgroup,

I'm using the JPOX implementation (www.jpox.org) of the JDO standard in a
Java web application. I now want to enable the logging functionality. As
described in the docs at http://www.jpox.org/docs/1_1/logging.html I have
to pass an argument to the JVM
(-Dlog4j.configuration=file:log4j.properties).

My question is now: How do I pass this web application specific argument to
the JVM? I'm using the NetBeans 5.0 IDE with the integrated Tomcat 5.5
server.

Signature

Sincerely
Sven Jacobs

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Finomosec - 20 Feb 2006 07:40 GMT

Sven Jacobs schrieb:

> Dear newsgroup,
>
[quoted text clipped - 7 lines]
> the JVM? I'm using the NetBeans 5.0 IDE with the integrated Tomcat 5.5
> server.

I only know how it works on a standard Tomcat installation.
We modify the catalina.sh and (as far as i remember) set the
CATALINA_OPTS-Variable to (in your case)
"-Dlog4j.configuration=file:log4j.properties".

Maybe you can configure the start-parameters from within your NetBeans
5.0 IDE.

Greetings Finomosec;

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Sven Jacobs - 20 Feb 2006 07:51 GMT

> I only know how it works on a standard Tomcat installation.
> We modify the catalina.sh and (as far as i remember) set the
[quoted text clipped - 3 lines]
> Maybe you can configure the start-parameters from within your NetBeans
> 5.0 IDE.

I didn't find such a setting in the NetBeans IDE... Can JVM arguments be
set in the web.xml or context.xml configuration files? This would be really
nice because I don't have to adjust another Tomcat server if I deploy the
application elsewhere.

How does the Tomcat server work internally? Will it startup a new JVM for
each web application it's running or will it use the same JVM which runs
the Tomcat server? If it's the first option then there must be a way to
tell Tomcat what arguments to pass to the JVM, right?

Signature

Sincerely
Sven Jacobs

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Robert Klemme - 20 Feb 2006 09:29 GMT

>> I only know how it works on a standard Tomcat installation.
>> We modify the catalina.sh and (as far as i remember) set the
[quoted text clipped - 9 lines]
> be really nice because I don't have to adjust another Tomcat server
> if I deploy the application elsewhere.

They can't. At the moment when these files are read the JVM is already up
and running.

> How does the Tomcat server work internally? Will it startup a new JVM
> for each web application it's running or will it use the same JVM
> which runs the Tomcat server? If it's the first option then there
> must be a way to tell Tomcat what arguments to pass to the JVM, right?

There is just a single JVM.

But properties can also be set at runtime:

http://java.sun.com/j2se/1.4.2/docs/api/java/lang/System.html#setProperties(java
.util.Properties)

http://java.sun.com/j2se/1.4.2/docs/api/java/lang/System.html#setProperty(java.l
ang.String,%20java.lang.String)

You could write initialization code that does this and execute it via a
listener that listens on application startup and shutdown events:

http://java.sun.com/products/servlet/2.3/javadoc/javax/servlet/ServletContextLis
tener.html

Regards

robert

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[Tomcat] How to pass application specific parameters to the JVM?

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