What is Public Static Void Main in Java?

The public static void main() is the most important java method. The compiler starts executing the java program from the main method. Hope you remember when you wrote your's first java program.

Now, the question is what are these prefixes i.e public, static, and void in the main() method? What are the uses of these terms in these questions? Can we avoid prefixes? Let's dive deep, and find the in-depth knowledge of these terms.

Why Do We Use Public Static Void Main in Java?

The main() method is used to execute the java program, whether it is a small program or a large codebase program, Now the question is can we run the java program without implementing the main() method? The answer is no, every java program must have a main() method to execute the program.

Let's understand the execution life cycle of the java program.

During the execution of any java program, the JVM(java virtual machine) search the main() method of the java program to execute that's why the main() method is marked by public specifier because the JVM externally calls the main() method for executing, and the scope of public specifier allows to access it. Refer to this article to understand the scope of the different modifiers. Access Modifiers in java.

Now the question arises, what will happen if we try to use another specifier in the main() method in the place of the public. Let's see using an example.

Output:

We can see clearly the java compiler will throw an error. if we try to use another specifier instead of the public in the main() method.

Why main() Method in Java Must be Static?

Let's understand what is the use case of static and the importance of the static method in the main() method.

We know very well, that we need to create an object of the class to access its method, and creating an object requires extra space in the memory, and we know very well we can access the static method of the class without creating an object of the class. Refer to this article Static member.

Let's understand them without the help of some examples.

Examples of Public Static Void Main in Java

Avoiding the Static keyword in the Main Method.

Let's understand what will happen if we avoid the static prefix in the main() method.

Output:

Changing the Position of the Public and Static keyword in the Main Method.

This is the most popular interview question that is what will happen if we interchange the position of the public and static keyword in the main() method.

Let's understand this using an example. In the example, we interchanged the position of the static and the public keyword.

Output:

We can interchange the position of the static and the public keywords in the main() method, but changing the position with other keywords like the void in the main() method will cause an error.

Parameter of the main() Method.

The main() method takes a String array[] as an argument that helps to take the value from the user.

Let's understand this using an example. In the below example, we are printing the length of the String array length, and the values of the first two indexes.

Output:

Learn more about Static Method in Java

Learn more about the static method in java Static method