Why and when to perform this task
Class loaders affect the packaging of applications and the run-time behavior of packaged applications deployed on application servers.
Steps for this task
The application class-loader policy controls the isolation of applications running in the system. When set to SINGLE, applications are not isolated; a single application class loader is used to contain all EJB modules, dependency JAR files, and shared libraries in the system. When set to MULTIPLE, applications are isolated from each other; each application receives its own class loader to load that application's EJB modules, dependency JAR files, and shared libraries.
The application class-loader mode specifies the class-loader mode when the application class-loader policy is SINGLE. PARENT_FIRST causes the class loader to first delegate the loading of classes to its parent class loader before attempting to load the class from its local class path. PARENT_LAST causes the class loader to first attempt to load classes from its local class path before delegating the class loading to its parent. This allows an application class loader to override and provide its own version of a class that exists in the parent class loader.