I used to be.. on Tomcat7 - The classloader magic world of a Monolith
I know that many of you probably don't use Tomcat for your applications deployment, but as you know there are tons of systems that currently run on this specific Application Server. Most of the existing Monoliths around the world are deployed on Tomcat (or Weblogic or whatever) where the classloader is - of course - managed by the Application Server itself. THE PROBLEM We have this very old application that is working without any problem on Tomcat7. This application has an extensive use of class scanning due to Jaxb implementation that search on every Jar file and create a JaxbContext of known classes. There was a request from customer to move the application from Tomcat7 to other Tomcat8 or Tomcat9, because the seven is out of standard for the company. Ehi: there are no problem. There are just fews properties in catalina.properties that we need to copy and "le jeux sont faits", we can easily deploy. And this is was we did but... Wait....whaaaaaat????? we have the corre...