As Java programs grow in complexity, organizing hundreds of classes becomes crucial. Just like folders on a computer help you group files logically, packages in Java serve the same purpose—organizing related classes into namespaces.
This logical grouping not only improves code readability and maintainability but also helps avoid class name conflicts, especially when using third-party libraries.
A package in Java is a namespace that organizes a set of related classes and interfaces. Think of it like a directory structure where each class is stored in a folder based on its category.
java.util, java.io, java.lang).Note: The java.lang package is automatically imported in every Java program, so classes like String, Math, and System can be used without importing explicitly.
Learn how packages are used in Java, the syntax for creating and importing packages, and best practices for modular programming.
// File: mypackage/Greeting.java
package mypackage;
public class Greeting {
public void sayHello() {
System.out.println("Hello from the package!");
}
}
// File: Main.java
import mypackage.Greeting;
public class Main {
public static void main(String[] args) {
Greeting g = new Greeting();
g.sayHello();
}
}
Organize thousands of classes in structured hierarchies, such as modules in enterprise software.
Distribute reusable components like logging utilities, data parsers, and more using packages.
Restrict access to internal classes and expose only public APIs via package-level access modifiers.
A package is a namespace that organizes a set of related classes and interfaces. It helps avoid name conflicts and improves code manageability.
Built-in packages are provided by Java (e.g., java.util), while user-defined packages are created by developers to group their own classes.
Use the import keyword, e.g., import java.util.Scanner; or import mypackage.*;.
The compiler can distinguish between them using their fully qualified names (e.g., package1.ClassName vs. package2.ClassName).