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What is main method?

Main Method

So, question is that why we need main method. Let’s take a real life example.

Suppose, you bought a movie ticket and entered into Multiplex. Now, How would you know which is your hall to see your movie. You just see your movie tickets and match all the details from the details showing in front of halls. Like movie name, timings and hall number and you entered into that hall and enjoying your movie.

         Same like this. A java program also needs some identification to run it. To                  achieve this, JVM has a default or pre-define structure or signature for this. This is below.

public static void main(String[] args){

}

As we have already learn about all the word which are use to define the main method. All are keywords and we know behaviors and purpose of each keyword. Except main, main is nothing but just a unique name to identify the method.

But now question is this, why we have public static void? Why we don’t have other modifiers or some other return types.

Let’s study that one by one. As we already learn that JVM need some identification point from where it will run a java program. So when the JVM was developed, that time the developer defined that this is the only method from where a Java program should starts.

We can make some of changes, but we will learn it later.

Okay, we agree that this is the default signature. But, why only public static void? Why not private String main() or something else.

Let’s discuss one by one.

public: This is a simple answer, if in case developer make it private and we know the behavior of private keyword. Then, how JVM will access the main method? That’s why it is public.

static: When we know that only JVM will going to call main method, then there is no need to make an object of the class. JVM will call main method by using class name.

void: There is no need to return anything by main method. Because, there is no other method will call after complete processing of main method. If, it will return something, then who will go to use that value? This is why main method does not return any value.

main: main is just a pre-define name which is we have to use to define main method.

String[] args: It is an String[] type of argument and args is a reference of String[] type, which is passed into main method. We will know more about this later.

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