JAVA program structure

In Java, a program follows a specific structure that consists of various elements. Here’s an overview of the basic structure of a Java program:

1. Package Declaration (optional):

You can start a Java program with a package declaration, which helps organize classes into different packages. It is not mandatory, but it is commonly used to provide a hierarchical structure to the code.

package com.example.myprogram;

2. Import Statements (optional):

Import statements are used to specify the classes or packages that are required by your program. They allow you to access classes from other packages without using their fully qualified names.

import java.util.Scanner;

3. Class Declaration:

Every Java program consists of at least one class, and the class declaration is the main entry point of the program. The class declaration includes the class name and the opening and closing curly braces.

public class MyProgram {
    // Class members and methods
}

4. Main Method:

The main method is a special method in Java that serves as the starting point of the program’s execution. It is declared within the class and has the following syntax:

public static void main(String[] args) {
    // Program logic
}

5. Class Members and Methods:

Within the class, you can define various class members such as fields (variables), methods, constructors, and nested classes. These members are declared inside the class and can be accessed by the class itself or its instances.

public class MyProgram {
    private int myVariable; // Field declaration

    public void myMethod() {
        // Method logic
    }

    public MyProgram() {
        // Constructor logic
    }

    public class NestedClass {
        // Nested class declaration
    }
}

6. Statements and Expressions:

Within the main method or other methods, you write statements and expressions to define the logic of your program. Statements are individual lines of code that perform specific actions, and expressions produce values or perform computations.

public static void main(String[] args) {
    int x = 5; // Statement
    int y = x * 2; // Statement with expression

    System.out.println("Result: " + y); // Statement with expression
}