How to Create a Package in Java?

Last Updated : 24 Jul, 2024

Package in Java is a mechanism to encapsulate a group of classes, sub-packages, and interfaces. All we need to do is put related classes into packages. After that, we can simply write an import class from existing packages and use it in our program. A package is a container of a group of related classes where some classes are accessible or exposed and others are kept for internal purposes. We can reuse existing classes from the packages as many times as we need them in our program. Package names and directory structure are closely related

Types of Packages in Java

There are two types of packages in java:

User-defined Package (Create Your Own Package's)
Built-in packages are packages from the java application programming interface that are the packages from Java API for example such as swing, util, net, io, AWT, lang, javax, etc.

In this article, we will see How To Create A Package In Java. A package is a group of similar types of Classes, Interfaces, and sub-packages. We use Packages to avoid name conflicts.

Syntax: To import a package

import package.name.*;

Example: Importing java.util package

Java

// Java Program to Import a package  // Importing java utility package import java.util.*;  // Main Class class GFG {      // Main driver method     public static void main(String[] args)     {          // Scanner to take input from the user object         Scanner myObj = new Scanner(System.in);         String userName;          // Display message         // Enter Your Name And Press Enter         System.out.println("Enter Your Name:");          // Reading the integer age entered using         // nextInt() method         userName = myObj.nextLine();          // Print and display         System.out.println("Your Name is : " + userName);     } }

Input

Enter Your Name:
geeksforgeeks

Output:

Your Name is : geeksforgeeks

Here In The Above Program, 'java.util' package is imported Scanner class is used to take input from the user. These are called as Inbuilt Packages.

Creating a Package in Java

Now in order to create a package in java follow the certain steps as described below:

First We Should Choose A Name For The Package We Are Going To Create And Include. The package command In The first line in the java program source code.
Further inclusion of classes, interfaces, annotation types, etc that is required in the package can be made in the package. For example, the below single statement creates a package name called “FirstPackage”.

Syntax: To declare the name of the package to be created. The package statement simply defines in which package the classes defined belong.

package FirstPackage ;

Implementation: To Create a Class Inside A Package

First Declare The Package Name As The First Statement Of Our Program.
Then We Can Include A Class As A Part Of The Package.

Example 1: Creating a Class Inside a Package

Java

// Name of package to be created package FirstPackage;  // Class in which the above created package belong to class Welcome {     // main driver method     public static void main(String[] args)     {         // Print statement for the successful         // compilation and execution of the program         System.out.println(             "This Is The First Program Geeks For Geeks..");     } }

So Inorder to generate the above-desired output first do use the commands as specified use the following specified commands

Procedure to Generate Output:

1. Compile the Welcome.java file:

Command: javac Welcome.java

2. This command creates a Welcome.class file. To place the class file in the appropriate package directory, use:

Command: javac -d . Welcome.java

3. This command will create a new folder called FirstPackage. To run the class, use:

Command: java FirstPackage.Welcome

Output: The Above Will Give The Final Output Of The Example Program.

Example 2: Another Package Example

Java

// Name of package to be created package data;  // Class to which the above package belongs public class Demo {      // Member functions of the class- 'Demo'     // Method 1 - To show()     public void show()     {          // Print message         System.out.println("Hi Everyone");     }      // Method 2 - To show()     public void view()     {         // Print message         System.out.println("Hello");     } }

Again, in order to generate the above-desired output first do use the commands as specified use the following specified commands

Procedure:

1. Compile the Demo.java file:

Command: javac Demo.java

2. This command will generate a Demo.class file:

Command: javac -d . Demo.java

3. This command will create a new folder called data containing the Demo.class file.

Note: In data Demo.java & Demo.class File should be present

Example 3: Accessing Data from Another Program

Java

// Name of the package import data.*;  // Class to which the package belongs class ncj {      // main driver method     public static void main(String arg[])     {          // Creating an object of Demo class         Demo d = new Demo();          // Calling the functions show() and view()         // using the object of Demo class         d.show();         d.view();     } }

Procedure to Generate the Output:

1. Compile the ncj.java file:

Command: javac ncj.java

2. The above command compiles ncj.java and requires the Demo.class file to be present in the data package.

Command: java ncj 
// To Run This File

Output: Generated on the terminal after the above command Is executed

Hi Everyone
Hello

Java Program to Create a File in a Specified Directory

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Java

How to Create a Package in Java?

Types of Packages in Java

Example: Importing java.util package

Creating a Package in Java

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