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Is Java a daemon?
Daemon thread in java is a service provider thread that provides services to the user thread. Its life depend on the mercy of user threads i.e. when all the user threads dies, JVM terminates this thread automatically. There are many java daemon threads running automatically e.g. gc, finalizer etc.
Is Main a daemon thread Java?
The main thread cannot be set as daemon thread. Because a thread can be set daemon before its running and as soon as the program starts the main thread starts running and hence cannot be set as daemon thread.
What is difference between daemon and non-daemon thread?
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 thread?
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.
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.
What is the use of daemon?
A daemon (pronounced DEE-muhn) is a program that runs continuously and exists for the purpose of handling periodic service requests that a computer system expects to receive. The daemon program forwards the requests to other programs (or processes) as appropriate.
What does the JVM do if a daemon is running?
JVM does not care whether Daemon thread is running or not. It is an utmost low priority thread. void setDaemon (boolean status): This method is used to mark the current thread as daemon thread or user thread.
Are there any daemon threads running in Java?
There are many java daemon threads running automatically e.g. gc, finalizer etc. You can see all the detail by typing the jconsole in the command prompt. The jconsole tool provides information about the loaded classes, memory usage, running threads etc. It provides services to user threads for background supporting tasks.
How to use the daemon interface in JSVC?
There two ways to use jsvc: via a Class that implements the Daemon interface or via calling a Class that has the required methods. For example Tomcat-4.1.x uses the Daemon interface whereas Tomcat-5.0.x provides a Class whose methods are called by jsvc directly. Write a Class that implements the Daemon interface (MyClass).
What kind of processes does JSVC use?
Jsvc uses 3 processes: a launcher process, a controller process and a controlled process. The controlled process is also the main java thread, if the JVM crashes the controller will restart it in the next minute. Jsvc is a daemon process so it should be started as root and the -user parameter allows to downgrade to an unprivilegded user.