I'm trying to manipulate json files using parser-json addon. I can save files but when I try to read them I receive a (classpath?) error:

Caused by: java.lang.LinkageError: loader constraint violation: when resolving interface method "org.jboss.forge.addon.parser.json.resource.JsonResource.getJsonObject()Ljavax/json/JsonObject;" the class loader (instance of org/jboss/modules/ModuleClassLoader) of the current class, com/github/forge/addon/music/PlaylistManager, and the class loader (instance of org/jboss/modules/ModuleClassLoader) for the method's defining class, org/jboss/forge/addon/parser/json/resource/JsonResource, have different Class objects for the type javax/json/JsonObject used in the signature
    at com.github.forge.addon.music.PlaylistManager.getAllPlaylists(PlaylistManager.java:178)
    at com.github.forge.addon.music.PlaylistManager.initPlayLists(PlaylistManager.java:57)

public List<JsonObject> getAllPlaylists() {
    List<JsonObject> playListsObject = new ArrayList<>();
    List<Resource<?>> playListsFound = getPlayListHomeDir().listResources(new ResourceFilter() {
        @Override
        public boolean accept(Resource<?> resource) {
            return resource instanceof FileResource && resource.getName().endsWith(".json");
        }
    });
    for (Resource<?> resource : playListsFound) {
        JsonResource jsonResource = resource.reify(JsonResource.class);
        JsonObject jsonObject = jsonResource.getJsonObject();
        playListsObject.add(jsonObject);
    }
    return playListsObject;
}