I have a legacy web app running in Tomcat 5.0.
This web app has two jars in WEB-INF/lib, let’s say Foo-2.0.jar and Bar-2.0.jar. Bar-2.0.jar actually includes a Foo-1.0.jar inside of it. Bar is also a dead project, meaning no upgrading, no source, but still important to the application.
The latest release of this application requires Foo-2.0.jar for some other stuff. Having both Foo-1.0.jar and Foo-2.0.jar in the classpath creates a conflict, specifically a ClassDefNotFound type of error, where a class that was later added in 2.0 cannot be found in 1.0, etc.
In Eclipse, the simple solution is to right click on your Project, click Properties > Java Built Path > Order and Export and to move Foo-2.0.jar above Bar-2.0.jar so it’s resolved first.
How does one accomplish this type of classpath ordering for jars in WEB-INF/lib in Tomcat?
Put Foo-1.0.jar to $CATALINE_HOME/common/endorsed (or any other place where it will be loaded after Foo-2.0.jar).