How to use a thread as daemon thread

In multithreading i have undergone through daemon thread concepts and its mentioned as low priority thread which runs in the background of garbage collection.
My query is how to make the thread daemon thread r we going to use thread priorities here.
Can anyone demonstrate with an example reg this. I will be very much thankful to them.

In general, threads that run application code are not daemon threads, and threads that run system code are daemon threads,so the daemon attribute is queried using the isDaemon() method; it is set using the setDaemon() method.....

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Thread Operation - daemon thread

What will be the output of the following program (with explaination)?
public class A extends Thread {
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setDaemon(true);
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Hi
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How to use a thread as daemon thread

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