What does mean by public static void main(String args[]) in Java?

Every program we write should have an entry point to start execution. the main method is the entry point of a Java program for the Java Virtual Machine(JVM). Let's take the below example to understand deeply.

When we run the above program JVM will search for the main method which is declared as public, static, and void.

Why main must be declared public?

public is an Access specifier in Java, which specifies from where and who can access the method.

main() must be declared as public because as we know it is invoked by JVM whenever the program execution starts and JVM do not belong to our program package.

In order to access the main outside the package, we have to declare it as public. If we declare it as anything other than public it shows a Run time Error but not a Compilation time error.

Why main must be declared static?

static is a keyword, main() must be declared as static because JVM does not know how to create an object of a class, so it needs a standard way to access the main method which is possible by declaring main() as static.

If a method is declared as static then we can call that method outside the class without creating an object using the syntax ClassName.methodName();

Why main must be declared void?

void is a keyword and used to specify that a method doesn’t return anything. As the main() method doesn’t return anything, its return type is void. As soon as the main() method terminates, the java program terminates too. Hence, it doesn’t make any sense to return from the main() method as JVM can’t do anything with the return value of it.

main()

It is the name of the Java main method. It is the identifier that the JVM looks for as the starting point of the java program. It’s not a keyword.

Why main must have String Array Arguments?

main() must have String arguments as arrays because JVM calls the main method by passing the command-line argument. As they are stored in string array objects it is passed as an argument to main().