protected void registerPluginJars() throws KettlePluginException { List<JarFileAnnotationPlugin> jarFilePlugins = findAnnotatedClassFiles( pluginType.getName() ); for ( JarFileAnnotationPlugin jarFilePlugin : jarFilePlugins ) { URLClassLoader urlClassLoader = createUrlClassLoader( jarFilePlugin.getJarFile(), getClass().getClassLoader() ); try { Class<?> clazz = urlClassLoader.loadClass( jarFilePlugin.getClassName() ); if ( clazz == null ) { throw new KettlePluginException( "Unable to load class: " + jarFilePlugin.getClassName() ); } List<String> libraries = Arrays.stream( urlClassLoader.getURLs() ) .map( URL::getFile ) .collect( Collectors.toList() ); Annotation annotation = clazz.getAnnotation( pluginType ); handlePluginAnnotation( clazz, annotation, libraries, false, jarFilePlugin.getPluginFolder() ); } catch ( Exception e ) { // Ignore for now, don't know if it's even possible. LogChannel.GENERAL.logError( "Unexpected error registering jar plugin file: " + jarFilePlugin.getJarFile(), e ); } finally { if ( urlClassLoader != null && urlClassLoader instanceof KettleURLClassLoader ) { ( (KettleURLClassLoader) urlClassLoader ).closeClassLoader(); } } } }