Structure of Java

 Java, being a versatile and object-oriented programming language, follows a structured format in its code organization. Here's a high-level overview of the typical structure of a Java program:

1. Package Declaration:

package com.example.myapp;

2. Import Statements:

• Import statements are used to bring in classes or entire packages from Java's standard library or external libraries.

 

import java.util.ArrayList;
import java.util.List;
    

    

3. Class Declaration:

• The main structure of Java revolves around classes. Every Java program must have at least one class, and the file name should match the name of the public class.

 

public class MyClass {
    // Class members go here
}
    

    

4. Main Method:

• The main method serves as the entry point for a Java program. It's where the program starts executing.

 

public class MyClass {
    public static void main(String[] args) {
        // Program logic goes here
    }
}
 

    

5. Class Members:

• Inside the class, you can define various members like fields (variables), methods, and other nested classes.

 

public class MyClass {
    // Fields (variables)
    private int myNumber;

    // Methods
    public void doSomething() {
        // Method logic
    }
}
 

    

6. Access Modifiers:

• Access modifiers (e.g., public, private, protected) control the visibility of classes, fields, and methods. They specify where these members can be accessed from.

 
 

public class MyClass {
    private int myNumber;  // private field

    public void doSomething() {
        // public method
    }
}
    

    

7. Constructor:

• Constructors initialize objects when they are created. If you don't provide one, Java creates a default constructor for you.

 
 

public class MyClass {
    private int myNumber;

    // Constructor
    public MyClass(int initialNumber) {
        this.myNumber = initialNumber;
    }
}
    

    

8. Comments:

• Comments are used to document the code. Single-line comments start with //, and multi-line comments are enclosed between /* and /.

 
 

// This is a single-line comment

/*
 * This is a multi-line comment
 * spanning multiple lines.
 */
    

    

9. JavaDoc Comments:

• JavaDoc comments are a special type of comment used for generating documentation. They start with /** and can include information about classes, methods, and fields.

 
  

/**
 * This is a JavaDoc comment for a class or method.
 */
    

    

This basic structure forms the foundation for Java programs. As your programs become more complex, you'll likely organize your code into multiple classes and packages, following principles like encapsulation, inheritance, and polymorphism in object-oriented programming.