The original text was taken from the blog - http://techtej.blogspot.com
There may be situations where you want to spawn a thread from your Activity or Service to handle long running (and may be blocking) tasks. In such cases, its sometimes necessary to pass data back and forth between the main thread and the worker thread(s). E.g. if the worker thread finishes a task and returns the result to the main activity to display the results OR you want to keep a worker thread around and ask it to switch between tasks depending on some message you pass to it.
There may be situations where you want to spawn a thread from your Activity or Service to handle long running (and may be blocking) tasks. In such cases, its sometimes necessary to pass data back and forth between the main thread and the worker thread(s). E.g. if the worker thread finishes a task and returns the result to the main activity to display the results OR you want to keep a worker thread around and ask it to switch between tasks depending on some message you pass to it.
