Daemon thread

Daemon thread

Daemon threads are low-priority threads whose only job is to offer assistance to user threads. Since daemon threads are intended to serve user threads and are just required while user threads are running, they will not keep the JVM from leaving once all client strings have completed their execution. That's why infinite loops, which commonly exist in daemon threads, won't cause issues because any code, including the final blocks, will not be executed once all user threads have completed their execution.
Thus, daemon threads are not suggested for I/O undertakings.

Some methods used are:

  • void setDaemon(boolean status)
  • boolean isDaemon()

Why does the JVM stop the daemon thread when there is no user thread?

The single objective of the daemon thread is that it gives services to the user thread for background helping jobs. When there is no availability of user thread, does the JVM keep running the thread? No, JVM stops the daemon thread when there is no user thread.

Various java daemon threads are operating automatically, e.g., gc, finalizer, etc.

Some tips to remember for Daemon Thread in Java

  • It gives services to user threads for background helping tasks. It has no use in life other than to serve user threads.
  • The survival of the Daemon thread depends on user threads.
  • Daemon thread is a low-priority thread.

Some of the methods for Java Daemon thread by Thread class

The java.lang.Thread class gives two methods for java daemon thread.

  • Public void setDaemon(boolean status):- It is used to check the current thread as daemon thread or user thread.
  • Public boolean isDaemon():- It is being used to verify that current is daemon.


Com.knowledge2life public class Main extends Thread{ public void run(){ if(Thread.currentThread().isDaemon()){//checking for daemon thread System.out.println("Knowledge2life"); } else{ System.out.println("Website"); } } public static void main(String[] args){ Main t1=new Main(); Main t2=new Main(); Main t3=new Main(); t1.setDaemon(true); t1.start(); t2.start(); t3.start(); } }