Plugin Classloader Release 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 a .jar extension. The JAR format is a ZIP archive that bundles a plugin with all of its dependencies.

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

Server classloader

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

Directory Description
XL_RELEASE_SERVER_HOME/conf For configuration files.
XL_RELEASE_SERVER_HOME/hotfix/lib/* For server hotfix JARs.
XL_RELEASE_SERVER_HOME/lib/* For server library JARs.

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

Plugin classloader

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

Directory Description
ext Directly 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 files to the classpath:

Directory Description
XL_RELEASE_SERVER_HOME/hotfix/plugins/* Can contain hotfix JARs for plugins.
XL_RELEASE_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.