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Version: Deploy 22.1

Plugins Classloader

Digital.ai Deploy runs on the Java Virtual Machine (JVM) and has two classloaders: one for the server itself, and one for the plugins and extensions. A plugin can have an .xldp or a .jar extension. The XLDP format is a ZIP archive that bundles a plugin with all of its dependencies.

To install or remove a plugin, you must stop the Digital.ai Deploy server. Plugins that are installed or removed while the server is running will not take effect until it is restarted.

Server classloader

The Digital.ai Deploy server classpath contains resources, configuration files, and libraries that the server needs to work. The default Digital.ai Deploy server classloader will use the following classpath:

DirectoryDescription
XL_DEPLOY_SERVER_HOME/confFor configuration files.
XL_DEPLOY_SERVER_HOME/hotfix/lib/*For server hotfix JARs.
XL_DEPLOY_SERVER_HOME/lib/*For server library JARs.

You can configure these directories in XL_DEPLOY_SERVER_HOME/conf/(xld-wrapper.conf.posix)|xld-wrapper.conf.win).

Plugin classloader

In addition to the Digital.ai Deploy server classloader, there is a plugin classloader. The plugin includes the classpath of the server classloader. It also includes:

DirectoryDescription
extDirectly added to the classpath and can contain classes and resources that are not in a JAR file.

The plugin classloader also scans the following directories and adds all *.jar and *.xldp files to the classpath:

DirectoryDescription
XL_DEPLOY_SERVER_HOME/hotfix/plugins/*Can contain hotfix JARs for plugins.
XL_DEPLOY_SERVER_HOME/plugins/*Contains installed plugins.

These paths are not configurable. The directories are loaded in the order that they are listed. This order is important. For example, hotfixes must be loaded before the code so that it can override the server behavior.