An in-depth discussion of the main() function in JAVA

Detailed explanation of the main() method in JAVA

In a JAVA program, the main() method is the entrance to the program and the starting point for program execution. The main() method is a necessary method for all JAVA applications. Every independently running JAVA program must contain the main() method.

The definition format of the main() method is as follows:

public static void main(String[] args) {
    // 程序代码
}

Next, we will analyze each part of the main() method in detail.

1. Modifier: The modifier of the main() method can be public, protected, private or not written, which is the same as the modifier of the class. Generally, we use the public modifier so that it can be called anywhere.
2. Return value type: The return type of the main() method is void, which means no value is returned.
3. Method name: The method name is main, which is the fixed name used by the JVM to identify the program entry.
4. Parameter list: The parameter list of the main() method is an array of String type. When starting the program on the command line, you can pass parameters to the main() method. The parameter name of the parameter list can be arbitrary and is generally represented by args.

public static void main(String[] args) {
    // 程序代码
}

In the main() method, we can write any legal JAVA code, call other methods, create objects, and perform various operations.

The following is a sample program:

public class MainMethodExample {
    public static void main(String[] args) {
        System.out.println("Hello World!");
    }
}

In the above sample program, we created a class named MainMethodExample and defined a main() method in the class. In the main() method, we use the System.out.println() method to print a "Hello World!" message.

Run the program in the command line, you can see that the program outputs the "Hello World!" message.

Summary:
The main() method is the entrance to the JAVA program, and its format is fixed to public static void main(String[] args). Any legal JAVA code can be written in the main() method. As the starting point of the program, various operations can be performed and other methods can be called. When starting the program mainly through the command line, you can pass parameters to the main() method.

The above is the detailed content of An in-depth discussion of the main() function in JAVA. For more information, please follow other related articles on the PHP Chinese website!