What is package in java

Java Package is used to group related classes .

• avoiding name conflicts: (two classes with the same name can exist in different packages).
• Reusability: packaged code can be imported and used anywhere. Packages are divided into two categories;

1. Build in packages(Packages from the java API
2. User-defined Packages (create your own packages)

Build in Package:
Built-in Packages comprise a large number of classes that are part of the Java API. Some of the commonly used built-in packages are:

• java.lang: Contains language support classes

• java.io: Contains classes for supporting input/output operations.

• java.util: Contains utility classes that implement data structures such as Linked Lists and Dictionaries, as well as support for date and time operations.

• java.applet: Contains classes for creating Applets.

• java.awt: Contains classes for implementing the components for graphical user interfaces (like buttons, menus, etc). 6)

Example: Using java.util.Random (Built-in Package)

import java.util.Random;   // built-in package

public class GFG{

    public static void main(String[] args) {

        // using Random class
        Random rand = new Random();   

        // generates a number between 0–99
        int number = rand.nextInt(100);  

        System.out.println("Random number: " + number);
    }
}

Output

User-defined Packages

User-defined Packages are the packages that are defined by the user.

Example:

package com.myapp;

public class Helper {
    public static void show() {
        System.out.println("Hello from Helper!");
    }
}

To use it in another class:

import com.myapp.Helper;

public class Test {
    public static void main(String[] args) {
        Helper.show();
    }
}