Exploring Class Organization with Packages in Java

Java Development (13 Part Series)

1 Getting Back to Java: A Journey Through One of the Most Versatile Languages
2 How to Set Up Your Environment to Start Java Development
… 9 more parts…
3 IntelliJ IDEA on Ubuntu: Begin Your Journey into Java Development!
4 Your First Java Project in IntelliJ IDEA: Creating a “Hello World” in Java
5 Exploring Classes and the Main Method in Java
6 Exploring Class Organization with Packages in Java
7 Variables and Data Types in Java
8 Understanding float and double in Java
9 Types: char and boolean
10 Exploring Non-Primitive Types in Java: A Dive into Object-Oriented Programming
11 Understanding Strings and Arrays in Java
12 Exploring the for Loop in Java
13 Exploring While and DoWhile in Java: Master Loop Structures with Practical Examples

In the Java world, organization is key, and packages play a vital role in achieving it. Packages act as virtual directories that group classes, making your projects more structured and scalable.

When you create a class without specifying a package, it resides in the default package. However, by using named packages like com.example.project, you not only improve your code organization but also adhere to Java’s common best practices. The package name reflects the directory structure—for instance, com.example.project indicates that the class is located in src/com/example/project/.

How to Access Classes from Other Packages?

This is where the import statement comes in. It allows you to use external classes in your code, either broadly (import package.*) or specifically (import package.Class).

Here’s an example:

package com.myProject.helloworld;  
import java.lang.*;  
import java.lang.Math;  

public class SquareRootOfTwentyFive {  
    public static void main(String[] args) {  
        System.out.println("The square root of twenty-five is:");  
        System.out.println(Math.sqrt(25));  
    }  
}  

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In this example, to use mathematical methods like Math.sqrt(25), you simply need to import the java.lang.Math class, one of Java’s many utility classes. This functionality enhances modularity and reusability, which are crucial for building robust and collaborative projects.

Let Java’s package system guide your project structure toward clean, scalable, and professional code.

Java Development (13 Part Series)

1 Getting Back to Java: A Journey Through One of the Most Versatile Languages
2 How to Set Up Your Environment to Start Java Development
… 9 more parts…
3 IntelliJ IDEA on Ubuntu: Begin Your Journey into Java Development!
4 Your First Java Project in IntelliJ IDEA: Creating a “Hello World” in Java
5 Exploring Classes and the Main Method in Java
6 Exploring Class Organization with Packages in Java
7 Variables and Data Types in Java
8 Understanding float and double in Java
9 Types: char and boolean
10 Exploring Non-Primitive Types in Java: A Dive into Object-Oriented Programming
11 Understanding Strings and Arrays in Java
12 Exploring the for Loop in Java
13 Exploring While and DoWhile in Java: Master Loop Structures with Practical Examples

原文链接：Exploring Class Organization with Packages in Java