What is daemon thread and what is its purpose?

3. Uses of Daemon Threads. Daemon threads are useful for background supporting tasks such as garbage collection, releasing memory of unused objects and removing unwanted entries from the cache. Most of the JVM threads are daemon threads.

What is daemon thread explain briefly with example?

A Daemon thread is a background service thread which runs as a low priority thread and performs background operations like garbage collection. JVM exits if only daemon threads are remaining. The setDaemon() method of the Thread class is used to mark/set a particular thread as either a daemon thread or a user thread.

What is daemon thread in Linux?

A “daemon” thread is one that is supposed to provide a general service in the background as long as the program is running, but is not part of the essence of the program. Thus, when all of the non-daemon threads complete, the program is terminated. Thus, the program terminates without printing any output.

What are daemon and non-daemon threads?

Daemon threads are low priority threads which always run in background and user threads are high priority threads which always run in foreground. User Thread or Non-Daemon are designed to do specific or complex task where as daemon threads are used to perform supporting tasks.

Why do we need daemon threads?

Daemon threads are used for background supporting tasks and are only needed while normal threads are executing. If normal threads are not running and remaining threads are daemon threads then the interpreter exits. When a new thread is created it inherits the daemon status of its parent.

Why do we need daemon thread?

What is the use of daemon thread?

Daemon thread in Java. Daemon thread is a low priority thread that runs in background to perform tasks such as garbage collection. Properties: They can not prevent the JVM from exiting when all the user threads finish their execution.

Can you join a daemon thread?

You can actually call . join on daemon threads, but it’s generally considered to be not good practice. You could get a daemon thread to set an Event just before it finishes, which one or more other threads check, but it’s simpler just to use a non-daemon thread and .

Is Garbage Collector A daemon thread?

Java Garbage Collector runs as a Daemon Thread (i.e. a low priority thread that runs in the background to provide services to user threads or perform JVM tasks).

How do you stop a daemon thread?

exit(). In Python, any alive non-daemon thread blocks the main program to exit. Whereas, daemon threads themselves are killed as soon as the main program exits. In other words, as soon as the main program exits, all the daemon threads are killed.

What is difference between Daemon and non daemon thread?

Difference between Daemon and Non Daemon (User Threads) is that: JVM waits for non-daemon threads to finish executing before terminate the main program. On the other hand, JVM doesn’t wait for daemon thread to finish.

How many types of thread in Java?

There are only two types of thread in Java, daemon and non-daemon, and only one simple difference between them. That difference has been explained here, and is explained in the API.

Is main thread is a daemon thread?

Any thread created by main thread, which runs main method in Java is by default non daemon because Thread inherits its daemon nature from the Thread which creates it i.e. parent Thread and since main thread is a non daemon thread, any other thread created from it will remain non-daemon until explicitly made daemon by calling setDaemon (true).

Is thread scheduler part of JVM or OS?

Thread scheduler in java is the part of the JVM that decides which thread should run. There is no guarantee that which runnable thread will be chosen to run by the thread scheduler. Only one thread at a time can run in a single process. The thread scheduler mainly uses preemptive or time slicing scheduling to schedule the threads.