The system class loader

The system class loader is the default class loader provided by the Java runtime. In EAServer, classes that cannot loaded by a custom class loader must be loaded by the system class loader, based on the search order specified by the server’s system class path settings. You cannot refresh these classes without restarting the server.

It can be more efficient to configure system class loaders for classes that are used server wide, as long as all components that use them require the same class versions, and you do not need to refresh the classes without restarting the server.