The Tomcat class loader loads all classes of the Tomcat server (the CATALINA_HOME/server/lib directory). The classes of the common directory of Tomcat (CATALINA_HOME/common/lib directory) are loaded by the application class loader and not by this Tomcat class loader. Applications have the visibility of the common classes and not the server classes. To have the visibility of the server class, the context must have the privileged attribute set to true. This class loader has the application class loader as its parent class loader.