Re: Loading order for jar files

From:

"Daniel Pitts" <googlegroupie@coloraura.com>

Newsgroups:

comp.lang.java.programmer

Date:

8 Dec 2006 10:54:47 -0800

Message-ID:

<1165604086.990106.150140@16g2000cwy.googlegroups.com>

Gugle wrote:

The problem is that another product uses the same common component, but
an older version of it :( ....and for some reason, they cannot upgrade
to the latest version of the jar...

Also, I found another weird workaround...I removed all the jar files,
added only my jar files firsrt and then the older version of the jar
file and restarted tomcat..it seems to work fine now..wondering if it
depends on the order in which the jar files are added to the
directory..

Daniel Pitts wrote:

Gugle wrote:

Hi all,
I have a query regarding the loading order of jar files in Tomcat. I
have 2 jar files and a class 'Test' is present in both of them. 1 jar
file has a newer version of the class file with extra methods. Tomcat
classloader takes only *.jar.(I tried specifying the exact name of the
jar..it didn't load it). Now when I use a method which is present only
in the newer version of the class file, tomcat throws a NoClassDefFound
error since it is loading the older jar. If i delete this old jar file,
then it works fine. So its confirmed that it is loading the older jar
file first. But due to some issues, it is mandatory for me to have both
the jar files. How does Tomcat decide the load order for jar files? Any
help would be most welcome.

Why do you need both jar files? If they define the same classes, then
you most likely don't need both jar files.

You're product and the other product should live in different spaces,
problem solved :-)
I actually don't know how tomcat works (I use resin), but I would be
willing to guess that you can install your webapp in a different
directory (or use a war file), and then you wont collide with the other
webapps in the container. That's how it works with Resin at least.