What does public void do in classes Java?

What does public void do in Java?

Overview of the Public Keyword in Java

In Java, the public keyword is one of the most fundamental keywords used to declare classes, interfaces, and methods. It is used to define the accessibility of a class, method, or interface. In this article, we will delve into the meaning of public void and explore its implications in Java.

What is public?

In Java, public is a keyword that makes a method, class, or interface public, meaning that it can be accessed from anywhere in the program. It is not just about visibility, but also about accessibility and usage. Public classes and methods can be accessed by other classes, or even classes from other packages.

What is void?

In Java, void is a keyword that indicates a method, class, or interface does not return any value. It means that the method or class has no return type or value. The function of void is to indicate that the method does not return any information or result to the caller.

What does public void do in Java?

The following is a summary of what public void does in Java:

• It declares a public method in a class.
• The method is called a method or static method (in a class context) or non-static method (in an instance context).
• It does not have a return type (as it does not return any value).
• It is accessible from anywhere in the program.
• It can be static or non-static.
• It can be instance or static.

How to declare a public void method in Java

Here is an example of how to declare a public void method in Java:

public class MyClass {

    public void myPublicMethod() {

        System.out.println("This is my public method.");

    }

}

How to call a public void method in Java

Here is an example of how to call a public void method in Java:

public class MyClass {

    public static void main(String[] args) {

        MyClass obj = new MyClass();

        obj.myPublicMethod();

    }

}

When to use public void

Use public void when you want to create a method that:

• Does not return any value.
• Does not have any side effects (i.e., it does not modify any external state).
• Can be called from any class, or from classes in any package.

When not to use public void

Do not use public void when you want to:

• Return a value (as it will not be visible to other classes).
• Have any side effects (i.e., it will modify external state).
• Need to be able to be called from a specific class or context.

Conclusion

In conclusion, public void is a fundamental keyword in Java that declares a public method in a class. It indicates that the method does not return any value and is accessible from anywhere in the program. By understanding the meaning and implications of public void, developers can write more efficient and effective code.

Table:

Attribute	Description
Return Type	Not specified
Visibility	Public
Accessibility	Global
Usage	Accessible from anywhere in the program
Instance or Static	Can be called from either instance or static context
Instance or Static	Can be called from either instance or static context

Example Use Cases:

• Database operations: You can use a public void method to perform database operations, such as creating a table or inserting data.
• File I/O: You can use a public void method to read or write files, such as reading a file from disk or writing to a file.
• Network communication: You can use a public void method to send or receive data over a network, such as sending a request to a web server or receiving a response from a web server.