Java Virtual Machine Architecture

The bounden duty of a runtime Java Virtual machine instance is to be responsible for running a Java program. When a Java program is started, a virtual machine instance is created. When the program shuts down, the virtual machine instance also dies. If you run three Java programs concurrently on the same computer, you will get three instances of the Java virtual machine. Each Java program runs in its own instance of the Java virtual machine.

The Java Virtual machine instance runs a Java program by invoking the main () method of an initial class. and this main () method must be common (public), static, return value void, and accept an array of strings as arguments. Any class that has such a main () method can be used as a starting point for the Java program to run.

public class Test {public static void main (string[] args) {//TODO auto-generated method stub
System.out.println ("Hello World");
}

}

In the example above, the main () method in the initial class of the Java program will be the starting point of the program's initial thread, and any other threads are started by this initial thread.

There are two types of threads inside a Java Virtual machine: The daemon thread and the non-daemon thread (Tengyun technology ty300.com). A daemon thread is typically used by a virtual machine, such as a thread that performs garbage collection tasks. However, a Java program can also mark any thread it creates as a daemon thread (Get started tutorial qkxue.net). The initial thread in the Java program-the one that started with main ()-is a non-daemon thread.

This Java program continues to run as long as any non-daemon threads are running. When all non-daemon threads in the program are terminated, the virtual machine instance automatically exits. If the security Manager allows, the program itself can be exited by invoking the runtime class or the exit () method of the System class.

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Java Virtual Machine Architecture