Class loading and update detection settings

Class loading and update detection settings

Overview

To configure use of class loaders by an application, from console, click...
Applications | Application Types | WebSphere enterprise apps | application_name | Class loading and update detection

If an application is running, changing an application setting causes the application to restart.

On stand-alone servers, the application restarts after you save the change.
On multiple-server products, the application restarts after you save the change and files synchronize on the node where the application is installed.

To control when synchronization occurs on multiple-server products, deselect Synchronize changes with nodes on the Console preferences page.

Settings

Override class reloading settings for Web and EJB modules

Whether to enable class reloading when application files are updated.
Selecting sets reloadEnabled to true in deployment.xml.
If an application's class definition changes, the application server run time stops and starts the application to reload application classes.
Settings in deployment.xml override settings for Web and EJB modules defined in...

ibm-web-ext.xmi
META-INF/ibm-application-ext.xmi

The Web container reloads JSPs only when the IBM extension jspReloadingEnabled in the jspAttributes of ibm-web-ext.xmi is set to true. You can enable JSP reloading during deployment on the JSP Reload Options page.

Data type Boolean
Default false

Polling interval for updated files

Number of seconds to scan the application's file system for updated files.
The default is the value of the reloading interval attribute in the IBM extension file of the EAR file...
META-INF/ibm-application-ext.xmi

This setting is the same as the field...
Reload interval in seconds

...on the application installation and update wizards.
To enable reloading, specify a value greater than zero (1 to 2147483647). To disable reloading, specify zero (0).
The reloading interval attribute takes effect only if class reloading is enabled.

Data type Integer
Units Seconds
Default 3

Class loader order

Whether the class loader searches in the parent class loader or in the application class loader first to load a class.
The default for development and WAS class loaders is...
Classes loaded with parent class loader first

The application can override classes contained in the parent class loader by specifying...
Classes loaded with local class loader first (parent last)

This action can potentially result in ClassCastException or LinkageErrors if we have mixed use of overridden classes and non-overridden classes.
The default is to search in the parent class loader before searching in the application class loader to load a class.
For the application to use the default configuration of Jakarta Commons Logging in WAS, set application class loader mode to...
Classes loaded with parent class loader first

To override the default configuration of Jakarta Commons Logging...

The application must provide the configuration in a form supported by Jakarta Commons Logging
Set the class loader mode to...
Classes loaded with local class loader first (parent last)

Set the class loader mode for each Web module in the application so that the correct logger factory loads.

WAR class loader policy

Whether to use...

Class loader for each WAR file in application (default)
Single class loader for application

Related concepts
Class loaders

Related tasks
Set the use of class loaders by an application
Set enterprise application files
Class loading

Related
Enterprise application settings
Class loader collection
JSP and JSF option settings
Application server settings