Daemon Thread Notes

1. 只要程式中的non-Daemon thread都結束了..
就算有Daemon Thread仍在執行中...
程式一樣會被強制結束...

最簡單的例子就是garbage collector thread..

2. 如果某個 Thread 是 daemon thread，則它所產生的所有 threads 天生就
具有 daemon 的特性

3. A daemon thread should be used for some background task that
might provide a service to the applications. e.g. a Server thread
listening on a port for the clients' requests.
出自http://www.vyomworld.com/source/show.asp?ScriptID=176

以下出自http://web.syr.edu/~maaljlay/daemon.html
4. Any Java thread can be a daemon thread. Daemon threads are service
providers for other threads or objects running in the same process as
the daemon thread. For example, the thread that runs the garbage
collector in Java is a daemon thread, In general, threads that run
application code are not daemon thread, and threads that run system
code are daemon threads

5. The run() method for a daemon thread is typically an infinite loop that
waits for a service request, perform the service, and wait for the next
service request. Daemon threads continue to execute until there are
no more threads for which services can be provided. At this time, the
daemon threads die and the java interpreter terminated its execution.

6. Daemon threads are typically independent threads within an application
that provide services for other objects within that same application

7. As result from the experiment, the daemon threads are equal in
priority of the conventional user threads, it is recommended to make
them in the lowest priority as the garbage collector thread in java.