Tomcat 4.1, 5.5 & 6.x classloader

When Tomcat 4 is started, it creates a set of class loaders that are organized into the following parent-child relationships, where the parent class loader is above the child class loader:
Bootstrap

System

Common
/ \
Catalina Shared
/ \
Webapp1 Webapp2 ...
The characteristics of each of these class loaders, including the source of classes and resources that they make visible, are discussed in detail in the following section.
When Tomcat 5 is started, it creates a set of class loaders that are organized into the following parent-child relationships, where the parent class loader is above the child class loader:
Bootstrap

System

Common
/ \
Catalina Shared
/ \
Webapp1 Webapp2 ...
The characteristics of each of these class loaders, including the source of classes and resources that they make visible, are discussed in detail in the following section.
When Tomcat 6 is started, it creates a set of class loaders that are organized into the following parent-child relationships, where the parent class loader is above the child class loader:
Bootstrap

System

Common
/ \
Webapp1 Webapp2 ...
The characteristics of each of these class loaders, including the source of classes and resources that they make visible, are discussed in detail in the following section.