> 13.2.1 | Threads

> Although small applications can be written without using threads longer applications should use them. The Java programming language is naturally multi-threaded which can make a substantial difference in the performance of your application. Therefore we recommend referring to Java descriptions on threads before making any choices about threading models. Threads can be created in two ways. A class can be a subclass of Thread or it can implement Runnable.
> For example, threads can be launched in startApp() and destroyed in destroyApp(). Note that destroying Java threads can be tricky. It is recommended that the developer read the Java documentation on threads. It may be necessary to poll a variable within the thread to see if it is still alive.