Different forms of main() method

Different writing style of main() method -

Valid forms of main() in Java

Below are different variants of main() that are valid.

Default form: Below is the most common way to write main() in Java.

class Test {
    public static void main(String[] args){
        System.out.println("Main Method");
    }
}

Output:
Main Method

Meaning of the main Syntax:

public:  JVM can execute the method from anywhere.
static:  Main method can be called without object.
void:    The main method doesn't return anything.
main():  Name configured in the JVM.
String[]: Accepts the command line arguments.

Order of Modifiers: We can change order positions of static and public in main() method.

class Test{
    static public void main(String[] args)
    {
        System.out.println("Main Method");
    }
}

Output:

Main Method

Variants of String array arguments: We can place square brackets at different positions and we can use var args (…) for string parameter.

class Test{
    public static void main(String[] args){
        System.out.println("Main Method");
    }
}

Output:

Main Method

class Test{
    public static void main(String []args)
    {
        System.out.println("Main Method");
    }
}

Output:

Main Method

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

        System.out.println("Main Method");
    }
}

Output:

Main Method

class Test{
    public static void main(String...args){
        System.out.println("Main Method");
    }
}

Output:

Main Method

Final Modifier String argument: We can make String args[] as final.

class Test{
    public static void main(final String[] args){
        System.out.println("Main Method");
    }
}

Output:

Main Method

Final Modifier to static main method: We can make main() as final.

class Test{
    public final static void main(String[] args)
     {
        System.out.println("Main Method");
    }
}

Output:

Main Method

synchronized keyword to static main method: We can make main() synchronized.

class Test{
    public synchronized static void main(String[] args)
    {
        System.out.println("Main Method");
    }

}

Output:

Main Method

strictfp keyword to static main method: strictfp can be used to restrict floating point calculations.

class Test{
    public strictfp static void main(String[] args)
       {
        System.out.println("Main Method");
    }
}

Output:

Main Method

Combinations of all above keyword to static main method:

class Test{
    final static synchronized strictfp static void main(String[] args)
    {
        System.out.println("Main Method");
    }
}

Output:

Main Method

Overloading Main method: We can overload main() with different types of parameters.

class Test{
    public static void main(String[] args){
        System.out.println("Main Method String Array");
    }
    public static void main(int[] args){
        System.out.println("Main Method int Array");
    }
}

Output:

Main Method String Array

Inheritance of Main method: JVM Executes the main() without any errors.
class A{ public static void main(String[] args){ System.out.println("Main Method Parent"); } } class B extends A{ }
Two class files, A.class and B.class are generated by compiler. When we execute any of the two .class, JVM executes with no error.
```
O/P: Java A
Main Method Parent
O/P: Java B
Main Method Parent
```

Method Hiding of main(), but not Overriding: Since main() is static, derived class main() hides the base class main.

class A{
    public static void main(String[] args){
        System.out.println("Main Method Parent");
    }
}

class B extends A{

    public static void main(String[] args){

        System.out.println("Main Method Child");

    }
}

Two classes, A.class and B.class are generated by Java Compiler javac. When we execute both the .class, JVM executes with no error.

O/P: Java A
Main Method Parent
O/P: Java B
Main Method Child

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Valid forms of main() in Java

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