The JAR file of a FileHandler plugin must contain a dependency descriptor stating the required libraries and must fully specify its classpath in the manifest of the JAR.
This allows to load each plugin independently and to verify the execution environment will meet its assumptions and requirements.
See the documentation of the
Dependency.xsd XML schema
for how to specify the library dependencies.
The manifest classpath may contain relative paths, which will be resolved against the plugin directory configured in the application settings. This way common libraries can be shared by multiple plugins.