What are packages ?

by

Packages group related classes and interfaces together and thus avoiding any name conflicts. From OOP’s point of view packages are useful for grouping related classes together. Classes are group together in a package using “package” keyword.

In Java, a package is a mechanism for organizing classes and interfaces into a hierarchical structure. It helps in organizing and categorizing related classes and interfaces, providing a way to manage and structure the code in a more modular and maintainable manner.

Key points about packages in Core Java:

  1. Namespace Control: Packages provide a way to avoid naming conflicts. By organizing classes and interfaces into packages, you can create a namespace for your classes, reducing the chances of naming clashes with classes from other packages.
  2. Access Control: Packages also provide access control. Classes and interfaces within a package are accessible to other classes in the same package without needing to use explicit access modifiers (like public, private, etc.). This helps in encapsulation and information hiding.
  3. Hierarchical Organization: Packages can be organized hierarchically. For example, you might have a package called com.example and within that, you could have sub-packages like com.example.util or com.example.gui. This hierarchy helps in organizing the codebase in a structured manner.
  4. Import Statements: To use classes or interfaces from another package, you need to use import statements. Import statements inform the compiler about the location of the classes/interfaces you want to use, allowing you to reference them by their simple names rather than their fully qualified names.

Here’s a simple example:

java
// Import statement
import com.example.util.UtilityClass;// Using a class from a package
public class Main {
public static void main(String[] args) {
// Accessing a class from the imported package
UtilityClass.doSomething();
}
}

In this example, com.example.util is a package, and UtilityClass is a class within that package. The import statement allows you to use the simple name UtilityClass instead of the fully qualified name com.example.util.UtilityClass.

Understanding and using packages is an essential part of Java development, contributing to code organization, maintainability, and reusability.