Explain main()

Rephrase

• Is it possible to overload main() method?
• Is it possible to declare main() method as private or protected or with no access modifier?
• Is it possible to declare main() method as non-static?
• Can main() method take an argument other than string array?

main() method

main() method must be implemented as below:

public class Main {
    public static void main(String[] args) {

    }
}

main() method must be public in order to make it accessible to JVM. As main() method is the entry point for Java program JVM must be able to access it.

main() method must be declared as static so that JVM can call main() without instantiating it’s class. If it’s non-static JVM has to call constructor of that class to create an instance. There will be an ambiguity if constructor of that class takes an argument and JVM might have to pass values based on constructor.

main() must have void return type. Any other type is not acceptable.

main() method’s argument must be string array. From the introduction of var args you can pass var args of string type as an argument to main() method as var args are also arrays.

Overloading main() method

A Java class can have any number of main() methods. But to run the Java class, class should have main() method with signature as public static void main(String[] args).

public static void main(String[] args) must be present to run Java program as it serves as entry point for any Java program (JVM calls this).

public class Main {

    public static void main(String[] args) {
        // I am the entry point
    }

    void main(int arg) {
        // do something
    }

    double main(float float1) {
        // do something
        return float1;
    }
}