public abstract class Application<T extends BaseAppConfig>
    implements ConfigAware<T>, ContextHandleAware, JsonDescriptorAware {

    //--- App ID and descriptor ---

    // Returns the ID of this application, which comes from the "kos.app.appId" field of the "descriptor.json" file:
    public String getAppId();

    // Returns the descriptor from this application's KAB file (descriptor.json):
    public JsonDescriptor getDescriptor();

    //--- Handle ---

    // Returns the application's handle:
    public Handle getHandle();

    // Returns the application's handle prefix:
    public String getHandlePrefix();

    //--- Config ---

    // Returns the application's config bean:
    public T getConfig();

    // Sets the application's config bean:
    public void setConfig(T config);

    //--- App directory and files ---

    // Returns the base directory of the application:
    public File getAppDir();

    // Adds the specified path to the base application directory and returns it as a File:
    public File getAppFile(String path);

    //--- Data directory and files ---

    // Returns the base directory of the application's local storage area:
    public File getDataDir();

    // Adds the specified path to the base application data directory and returns it as a File:
    public File getDataFile(String path);

    //--- Context and VFS ---

    // Returns this applicaton's bean context:
    public BeanContext getCtx();

    // Returns the root VFS (virtual file system) for this application:
    public VFS getVfs();

    //--- KAB file and related ---

    // Returns the application KAB file, allowing for direct access to it contents:
    public KabFile getKab();

    // Returns the resolved manifest section associated with the application:
    public ResolvedManifestSection getSection();

    // Returns the storage domain associated with the application:
    public StorageDomain getStorage();

    //--- Databases ---

    // Opens or creates a database with the specified name in the local storage area of the application:
    public Jdbi openDatabase(String name, DatabaseMigrator migrator);

    //--- Profiles ---

    // Returns true if the given profile is in effect:
    public boolean hasProfile(String profile);

    //--- Methods called by KOS during the application's lifecycle ---

    // Called when the application is first loaded; used for application initialization:
    public void load() throws Exception;

    // Called when the application is started. Once this returns, the application is considered to be running:
    public abstract void start() throws Exception;

    // Called after start() returns. When this is called, all application VFS and endpoints are available:
    public void started() throws Exception;

    // Called to stop the application:
    public abstract void stop() throws Exception;

    // Called when the application is unloaded from memory:
    public void unload() throws Exception;
}

public abstract class SystemApplication<T extends BaseAppConfig> extends Application<T> {

    // Installs an assembly; simply calls AssemblyService.install():
    public void installAssembly(Assembly assembly);

    // Installs regions for the application:
    public void installRegions(Collection<BaseRegion> regions);

    // Install regions for the application with a custom settings bean:
    public void installRegions(Collection<BaseRegion> regions, RegionSettings settings);

    // System applications are never stopped:
    public void stop() throws Exception;
}

public class BaseAppConfig extends ConfigBean {

    //--- These methods come from the ConfigBean class ---

    // Returns true once the bean is configured:
    public boolean isConfigured();

    // Returns the associated ready indicator:
    public ReadyIndicator getReady();

    // Adds a listener to the list:
    public void addListener(ConfigBeanListener listener);

    // Removes a listener from the list:
    public void removeListener(ConfigBeanListener listener);
}

@Slf4j
public class ApplicationModule implements Module {

    private MyKosApp myKosApp;

    @Override
    public void init(BeanContext ctx) {
        log.info("> ApplicationModule.init()");
        myKosApp = ctx.getBean(MyKosApp.class);
    }

    @Override
    public void run() {
        log.info("> ApplicationModule.run()");

        log.info("> appId           : {}", myKosApp.getAppId());
        log.info("> descriptor.json : {}", myKosApp.getDescriptor().getRoot().toPrettyString());

        log.info("> appDir          : {}", myKosApp.getAppDir());
        log.info("> dataDir         : {}", myKosApp.getDataDir());

        log.info("> appFile         : {}", myKosApp.getAppFile("bogus1.txt"));
        log.info("> dataFile        : {}", myKosApp.getDataFile("bogus2.txt"));

        log.info("> handle          : {}", myKosApp.getHandle());
        log.info("> handlePrefix    : {}", myKosApp.getHandlePrefix());
        log.info("> config          : {}", myKosApp.getConfig());
    }
}

> ====== BEGIN =========================================
> MyKosApp.load()
> ApplicationModule.init()
> MyKosApp.start()
> ApplicationModule.run()
> appId           : system      (1)
> descriptor.json : {           (2)
  "kos" : {
    "app" : {
      "appClass" : "com.example.MyKosApp",
      "appId" : "system"
    }
  }
}
> appDir          : /mnt/fuse/app_system                            (3)
> dataDir         : /mnt/datafs/myNodeType/apps/system              (4)
> appFile         : /mnt/fuse/app_system/bogus1.txt                 (3)
> dataFile        : /mnt/datafs/myNodeType/apps/system/bogus2.txt   (4)
> handle          : system.app                                      (5)
> handlePrefix    : null
> config          : com.tccc.kos.core.service.app.BaseAppConfig@1a0e2b15
> ====== END ===========================================